Friday 15 December 2023, 16:00: Mieczyslaw Witold Krasny (LPNHE, Sorbonne University Paris & CERN) -- G08, Roberts Building

Gamma Factory -- a tool-driven revolution?

In this talk, I shall present the Gamma Factory project, being developed at CERN over the last 7 years. Its goal is to broaden significantly the present CERN research programme by including a new component which can be open by the novel-type light source. The proposed, partially-stripped-ion-beam-driven light source is the backbone of the Gamma Factory project. It could be realized at CERN by re-using the infrastructure of the already existing accelerators and by profiting from the recent progress in the laser technology. It could extend the scientific life of the LHC storage rings beyond its HL-LHC phase. Gamma Factory could push the intensity limits of the presently operating light-sources by at least 7 orders of magnitude, reaching the flux of up to 10^18 photons/s, in the particularly interesting gamma-ray energy domain of 0.1 — 400 MeV, which is presently nor accessible to the FEL photon sources. The partially stripped ion beams, the unprecedented-intensity energy-tuned gamma beams, together with the gamma-beam-driven secondary beams of polarized positrons, polarized muons, neutrinos, neutrons, and radioactive ions constitute the basic research tools of the Gamma Factory. A broad spectrum of new research opportunities, in a vast domain of uncharted fundamental and applied physics territories, could be opened by the Gamma Factory. Examples of new research opportunities and the status of the project development will be presented in this talk. 

Friday 8 December 2023, 16:00: Julia Harz (Mainz) -- G08 Roberts Building

Confronting Dark Matter Freeze-In during Reheating with Constraints from Inflation

I will discuss the production of Dark Matter (DM) in a minimal freeze-in model, specifically considering a non-instantaneous reheating phase after inflation. I will demonstrate that for low reheating temperatures, bosonic or fermionic reheating from monomial potentials can lead to a different evolution in the DM production and hence to distinct predictions for the parent particle lifetime and mass, constrained by long-lived particle (LLP) searches. I will demonstrate that the extent to which the standard DM freeze-in production can be modified crucially depends on the underlying inflationary model. Our findings underscore the impact of the specific dynamics of inflation on DM freeze-in production and highlight their importance for the interpretation of collider signatures.

Monday 27 November 2023, 13:00: Robert Svoboda (University of California, Davis) -- Physics A1/3 (NOTE UNUSUAL DATE + TIME)

A Hybrid Optical Detector for Neutrino Physics

Many of our breakthroughs in neutrino physics over the last three decades came as a result of new technology that allowed kiloton scale detectors with good particle tracking and energy resolution to be placed deep underground. In this talk, I will present the physics case for Theia, a large hybrid optical detector being proposed for the new Sanford Underground Research Facility (SURF) now under construction. Theia would use novel target materials, fast timing, excellent energy resolution, and photon spectral sorting to enable a broad program in neutrino physics using both the beam from the new Long Baseline Neutrino Facility and from natural neutrino sources. I will review the physics of Theia and give a summary of the several large demonstrators now under construction.

Friday 10 November 2023, 16:00: Graham Van Goffrier (UCL) -- B20, Drayton House

Chiral EFT for 0𝜈𝛽𝛽 Decay

Neutrinoless double-beta (0𝜈𝛽𝛽) decay is an as-yet unobserved nuclear process, which stands to provide crucial insights for model-building beyond the Standard Model of particle physics. Its detection would simultaneously confirm the hypothesis that neutrinos are Majorana fermions, thus violating lepton-number conservation, and provide the first measurement of the absolute neutrino mass scale. In this talk, I will explore the formulation of 0𝜈𝛽𝛽-decay within chiral effective field theory. I will review the justifications for a renormalisation-enhanced "contact term", a short-range two-nucleon effect which is unaccounted for in traditional nuclear approaches to the process, and highlight the most precise computation of its size to date, whose precision is limited by a truncation to elastic intermediate hadronic states. I will then show how an extension of this analysis to a subleading class of inelastic intermediate states can reduce the uncertainty on the contact coefficient by half, delivering an updated value for this important quantity. Such ab initio nucleon-level calculations represent inputs for nuclear many-body methods, and show promise for the resolution of large disparities between 0𝜈𝛽𝛽 nuclear matrix-element estimates from different many-body methods.

Friday 27 October 2023, 16:00: Rebeca Beltran Lloria (Instituto de Física Corpuscular) -- Drayton House B20

Exploring heavy neutral leptons at the LHC: phenomenology beyond the minimal scenario

Searches for heavy neutral leptons (HNLs) at the LHC have received increasing attention recently. In the minimal scenario, HNLs are produced and decay through mixing with active neutrinos. However, in non-minimal extensions, HNL interactions are often described within the context of effective field theories (EFTs). In this seminar, we will explore the signatures of GeV scale HNLs at the LHC and the sensitivity of the future far detectors to different HNL scenarios. We investigate first the production of HNLs directly in proton-proton collisions and second, the scenario where they are sufficiently light to be produced in meson decays, all following an EFT approach, where HNLs are typically long-lived owing to the suppression of the effective interactions by a very high new physics energy scale.

Friday 20 October 2023, 16:00: Brian Foster (Oxford) -- Chris Ingold Ramsay G21

A Hybrid, Asymmetric, Linear Higgs Factory based on Plasma Acceleration - the HALHF concept

Plasma-wakefield acceleration promises orders of magnitude higher gradients than can be achieved via conventional radio-frequency cavities. It is now starting to be used in real user facilities. However, its application to particle-physics colliders has always been complicated by the difficulty in accelerating positrons. I will introduce the basics of plasma wakefield acceleration and explain the difficulty with accelerating positrons. HALHF avoids this by using a conventional linac to accelerate positrons, resulting in an asymmetric-energy, hybrid linear facility which is much smaller, greener and cheaper than any conventional alternative Higgs-factory proposal. I will outline the HALHF layout and principles, and the R&D path to making it a reality.

Friday 23 June 2023, 16:00: Maxwell Chertok (University of California, Davis)

The High Luminosity LHC CMS Outer Tracker Upgrade

The venerable CMS silicon strip tracker has detected charged particles emanating from high energy LHC proton-proton collisions at increasingly higher energies since its debut in 2008. Data from this detector played a major role in the Higgs boson discovery in 2012, and is centrally used in virtually every data analysis. Radiation damaged and with a data readout too slow for inclusion in the Level-1 trigger, the tracker will be replaced for the upcoming High Luminosity LHC (HL-LHC) era. In this talk, I present the HL-LHC Outer Tracker upgrade, a complete replacement for the strip tracker using state-of-the-art components, materials, and electronics. I will focus on OT detector mechanics and the status of the detector production.

Friday 19 May 2023, 16:00: Suchita Kulkarni (University of Graz)

Exploring strongly interacting dark matter

Understanding the laws governing the dark matter dynamics in the Universe is undoubtedly one of the pressing questions inastro-particle physics. While investigations have focused on elementary particles as potential dark matter candidates, an equally interesting possibility arises if dark matter is a composite particle instead. I will take an overview of construction of such dark matter theories by extending the Standard Model with new non-Abelian sectors. I will further illustrate the benefits of connecting these constructions with lattice calculations. I will sketch the avenues of progress and highlight some of the open questions in this direction. Finally, I will exemplify the experimental signatures and impact of dark matter phenomenology.

Friday 5 May 2023, 16:00: Thomas Teubner (Liverpool)

The puzzles of g-2: a status update

In this talk we will review the status of g-2 of the muon. The main emphasis will be on the Standard Model prediction and in particular the determination of the hadronic contributions which are the limiting factor. Recent developments, the current state of the discrepancy between experiment and theory as well as future prospects to resolve the puzzles will be discussed.

Friday 28 April 2023, 15:00: Tomas Gonzalo (KIT)

Global studies of beyond the Standard Model theories: dark matter and supersymmetry

Beyond the Standard Model (BSM) theories aim to explain some of the missing ingredients of the Standard Model, yet no clear evidence for any of them has been found so far. Furthermore, most of these models introduce many new parameters, and make strong predictions for a multitude of experimental searches in particle physics, astrophysics and cosmology. Therefore, contrasting these theories with experimental data requires smart strategies to sample complicated parameter spaces and perform rigorous combinations of experimental results from many sources. In this talk I will introduce GAMBIT, a tool developed to make statistical studies of BSM theories easy and fast, and allow the study of models with many parameters and multiple experimen- tal searches. I will also show the results of various global studies of dark matter and supersymmetric models, where I will focus on their survival status in light of recent data and also on highlighting potential strategies to explore the remaining unconstrained parameter regions.

Friday 21 April 2023, 16:00: Peter Bradshaw (UCL)

Uncovering the Secrets of Symmetries

Symmetries form a foundational part of the modern particle physics programme, from the interactions between particles to the very structure of the space-time they inhabit. We traditionally construct physical models out of representations of a given set of symmetries, associating collections of these representations with primitive physical objects such as the fields of elementary particles. The formalism of representation theory is well-developed and understood mathematically, and physicists have no trouble using them to extract phenomenological predictions. However, the physical interpretation of a representation is often not straightforward and sometimes requires additional notions outside the domain of the symmetry; this is also true when considering the similarities and differences between the physical properties of two different representations. In this talk, we will begin to overcome these difficulties and reveal the hidden physical structures within a representation. First, we will consider the usual approach to representation theory and motivate a new approach in terms of associative algebras. We will then consider an example of such methods applied to the symmetry governing non-relativistic spin and naturally entail the identification of physical properties beyond spin eigenstates. Finally, we will explore the potential that further studies of this kind may have for the myriad symmetries of particle physics

Thursday 23 March 2023, 16:00: Asli Abdullahi (Fermilab)

Exotic $e^+e^-$ production at MicroBooNE

We present a phenomenological study of MicroBooNE’s ability to investigate $e^+e^-$ final states produced in dark photon mediated neutrino-upscattering—a beyond-Standard Model process proposed as a solution to the MiniBooNE anomaly. Utilising the similarities shared between the observable signatures of neutrino-induced $e^+e^-$ and single photons originating in the radiative decays of the $\Delta(1232)$ resonance, we consider MicroBooNE’s recent public data from its search for neutral current $\Delta(1232)$ radiative decays to test benchmark models of $e^+e^-$ production, and investigate MicroBooNE’s sensitivity to heavy neutrino models in which the neutrino sector is strongly coupled to a dark sector.

Friday 17 March 2023, 16:00: Sinead Farrington (Edinburgh)

Precision at the LHC

Precision at the LHC will continue to challenge theoretical calculations and tools. In this seminar I will discuss some of the LHC’s precision measurements in recent years, trends in them, and will shamelessly seek audience input to a workshop being organised later this year on the topic of legacy precision at the HL-LHC; what to work towards and how to achieve it.

Friday 10 March 2023, 16:00: Sukanya Sinha (Manchester)

Not a jet all the way - an exploration of strongly interacting dark sector in ATLAS and beyond

As classic WIMP-based signatures for dark matter at the LHC have found no compelling evidence, several phenomenological studies have raised the possibility of accessing a strongly-interacting dark sector through new collider-event topologies. If dark hadrons exist, their evolution and hadronization procedure are currently little constrained. They could decay promptly and result in QCD-like jet structures, even though the original decaying particles are dark sector ones; they could behave as semi-visible jets (SVJ); or they could behave as completely detector-stable hadrons. ATLAS and CMS have recently come up with the first results, but this is only the beginning. In this talk, I will discuss the public results of the first t-channel ATLAS search for semi-visible jets, and the multiple pioneering studies we have performed on SVJ, covering three published or soon to be published papers. Finally, although not related to SVJ, I will cover our published work about an innovative search for dark photons in events with a top quark and a lepton jet

Friday 24 February 2023, 16:00: David Yallup (Cambridge)

Evidence is all you need: Nested Sampling for particle physics

The Bayesian vs. Frequentist debate has raged for many years in particle physics, with the battle lines largely drawn and a set of established techniques falling firmly in favour of frequentist thinking. The same is largely true on the cosmology side of the fence, where the dominant paradigm is decidedly Bayesian. This is a curious fact that is worth considering, how have two adjacent fields that are so similar in ultimate goals and theoretical basis ended up at loggerheads when it comes to inference? To try and unravel some of this mystery, this talk will discuss the ‘Rosetta Stone’ of inference tasks in particle physics – searching for bumps in smoothly falling spectra at colliders. I will aim to extract the signal (the higgs) from the noise (the diphoton background), however in doing so I will really be attempting to extract the signal (why we use Nested Sampling so much in Cosmology) from the noise (the Bayesian vs. Frequentist debate). An “evidence based” approach (powered by Nested Sampling) affords unique perspectives on some long standing inference problems for High Energy Physics.

Friday 17 February 2023, 16:00: Seb Jones (UCL)

The QTNM collaboration: a project for absolute neutrino mass measurement

The observation of neutrino oscillations provides proof of non-zero neutrino masses, something which was not predicted in the minimal Standard Model. However, these same neutrino oscillation experiments do not provide information on the absolute scale of the neutrino masses, which remain unknown. The neutrino masses are most directly accessed through those experiments which measure the shape of the beta-decay energy spectrum. In particular, a technique known as Cyclotron Radiation Emission Spectroscopy (CRES) offers the opportunity to measure neutrino masses lower than the current upper mass limit of 0.8 eV/c^2 achieved by the KATRIN collaboration. The Quantum Technologies for Neutrino Mass (QTNM) collaboration aims to utilise CRES, along with recent breakthroughs in quantum technologies, to build a demonstrator apparatus for measuring the neutrino mass. It is hoped that this demonstrator will make significant contributions towards an experiment with a neutrino mass sensitivity of O(10 meV). I will present an overview of the principles of neutrino mass measurement as well as the QTNM collaboration.

Friday 20 January 2023, 16:00: Dieter Roehrich (Bergen)

Proton-CT - imaging with protons in particle therapy

A novel imaging modality using protons promises to overcome some limitations of particle therapy. Being able to position the Bragg peak accurately inside the tumor is a major advantage of charged particles, but incomplete knowledge about a crucial tissue property, the stopping power, limits its precision. A proton/helium-CT scanner provides direct information about the stopping power and has the potential to reduce range uncertainties significantly. A (clinical) prototype of a proton-CT has been designed and is being constructed in Bergen. The latest developments in Monolithic Active Pixel Sensors (MAPS) technology allow the fabrication of an extremely high granularity, large area silicon/absorber sandwich calorimeter with 41 sensitive layers of MAPS. A complete CT reconstruction of a simulated anthropomorphic paediatric head phantom shows that the concept of a single-sided detector setup and realistic pencil beam parameters gives a spatial uncertainty and a stopping power resolution sufficient for proton therapy treatment planning. The expected performance based on simulations, first beam test results and the status of the construction will be presented.

Friday 2 December 2022, 16:00: Matthew Mccullough (CERN)

The Higgs Boson Under a Microscope

What does the Higgs boson look like if you put it under a microscope? How does it move? Is it made up of smaller parts? Does it give itself mass? In this talk I will sketch a theoretical range of possible answers to these questions and, ultimately, how we might hope to answer them with the HL-LHC and future colliders.

Friday 18 November 2022, 16:00: Giacomo Magni (Nikhef)

Evidence for intrinsic charm quarks in the proton

QCD, describes the proton in terms of quarks and gluons. The proton is a state of two up quarks and one down quark bound by gluons, but quantum theory predicts that in addition there is an infinite number of quark-antiquark pairs. Both light and heavy quarks, whose mass is respectively smaller or bigger than the mass of the proton, are revealed inside the proton in high-energy collisions. However, it is unclear whether heavy quarks also exist as a part of the proton wavefunction, which is determined by non-perturbative dynamics and accordingly unknown: so-called intrinsic heavy quarks. After a brief introduction how parton distribution functions (PDFs) can be extracted from high energy data, we provide a first evidence for intrinsic charm by exploiting a high-precision determination of the quark-gluon content of the nucleon based on machine learning and a large experimental dataset. We disentangle the intrinsic charm component from charm-anticharm pairs arising from high-energy radiation, showing a generally good agreement with models. Finally we show how these findings can be compared to recent data on Z-boson production with charm jets from the LHCb experiment.

Friday 11 November 2022, 16:00: Andrew Stevens (UCL)

First results from LUX-ZEPLIN

The LUX-ZEPLIN (LZ) experiment is a dark matter detector centred on a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility in Lead, South Dakota, USA. Results from LZ's first search for Weakly Interacting Massive Particles (WIMPs) with an exposure of 60 live days using a fiducial mass of 5.5 tonnes were recently published. A profile-likelihood analysis shows the data to be consistent with a background-only hypothesis, setting new limits on spin-independent WIMP-nucleon cross-sections for WIMP masses above 9 GeV/c2 . The most stringent limit is set at 30 GeV/c2 , excluding cross sections above 5.9 × 10−48 cm2 at the 90% confidence level. This talk will give an overview of the LZ detector, a description of the first results, and a brief look at the science program that is now accessible with the LZ experiment.

Friday 28 October 2022, 16:00: Lydia Beresford (DESY)

Measuring tau g-2 using Pb+Pb collisions

The electromagnetic moments of the tau lepton are highly sensitive to new physics but are challenging to measure due to the short tau lifetime. Recently, the ATLAS and CMS Collaborations set the first new constraints on the tau magnetic moment (‘g-2’) in nearly two decades, using LHC heavy ion collisions as an intense source of photon collisions to observe photo-production of tau pairs in Pb+Pb collisions. In this seminar I will discuss these new results and I will also highlight exciting future prospects.

Friday 21 October 2022, 16:00: Sonia Escribano Rodriguez (UCL)

Prompt gamma-ray imaging of nanoparticles for in vivo range verification in proton therapy

Proton therapy is an emerging modality for cancer treatment. It produces a better dose conformation, reducing the damage to the surrounding healthy structures and tissues. However, in vivo range verification is desirable to minimize beam delivery errors during the treatment. The most promising range verification technique is prompt gamma-ray imaging (PGI). In addition, the use of nanoparticles (NPs) in proton therapy has been developed in the past years, as particles with high atomic number produce an enhancement in the dose received by the tumor. The aim of the project is to investigate the feasibility of performing prompt gamma-ray imaging measurements using characteristic gamma rays emitted from a nanoparticles target. To test the proof of principle an in-house designed target, consisting of a solution of magnetite NPs (Fe3O4) diluted in water, was irradiated with a proton beam at different energies. Two different detection systems were placed perpendicular to the target to measure the prompt gamma-rays emitted from the NPs after the proton irradiation. The experimental results, obtained at KVI-CART and the University of Birmingham, are compared to a Geant4 Monte Carlo simulation.

Friday 17 June 2022, 16:00: Rafael Teixeira De Lima (SLAC)

Exploring Di-Higgs production with beauty quarks and Machine Learning

The Standard Model of particle physics dictates how our universe works. Decades of experimental research have probed it in details. In the last 10 years, the final piece of the puzzle, the Higgs boson, has been discovered and studied to great precision. However, one area of the Standard Model remains a mystery: the Higgs potential. Determining the parameters of the Higgs potential can have significant implications in the nature of the electroweak symmetry breaking (the process by which fundamental particles acquire mass) and the history of the universe. In this talk, I will explore how we study the Higgs potential at the Large Hadron Collider (LHC) through the search for events where two Higgs bosons are produced (Di-Higgs). In particular, I will describe how the ATLAS experiment at the LHC conducts this search via the Higgs decays to beauty quarks. This search is only possible through the use of different Machine Learning algorithms, which will also be discussed.

Friday 10 June 2022, 16:00: Kevin Lesko (LBL)

Low Background Assay & Cleanliness Requirements for Future Rare-Search Experiments

I will review low background assay for fixed contaminants and surface cleanliness efforts from SNO, LUX, and LZ. Future large-scale rare-search experiments such as a G3 LXe or Neutrinoless Double-beta Decay may benefit from these experiences and lessons-learned. The challenges of large scale, underground construction efforts, and increasingly lower acceptable levels of fixed contamination are examined.

Friday 27 May 2022, 16:00: Robin G. Stuart

Searching For Shackleton’s Vessel Endurance – in the numbers

On 21 November 1915 Sir Ernest Shackleton’s vessel Endurance was crushed by ice in the Weddell Sea and sank at a position given as 68°39¢30²S 52°26¢30²W. Close examination of the sextant sights recorded in Captain Frank Worsley’s original logbooks showed, however, that the location of the wreck would be offset from this position. The navigational methods and calculations that Worsley used to fix the position will be discussed as well as the reanalysis of the observations using modern techniques. Lunar occultation timings, performed in the southern winter of 1915 to rate the chronometers for longitude, were reduced using JPL ephemerides for the Moon and Hipparcos star positions and yield results that are significantly different from those obtained from tables in the Nautical Almanac of the time. Various factors are at play but when taken together they predicted that the wreck should lie to the south and likely to the east of the recorded position.

Friday 13 May 2022, 16:00: Chris Hays (Oxford)

High-precision measurement of the W boson mass with the CDF II detector

The mass of the W boson, a mediator of the weak force between elementary particles, is tightly constrained by the symmetries of the standard model of particle physics. The Higgs boson was the last missing component of the model. After the observation of the Higgs boson, a measurement of the W boson mass provides a stringent test of the model. We measure the W boson mass using data corresponding to 8.8 inverse femtobarns of integrated luminosity collected in proton-antiproton collisions at a 1.96 TeV centre-of-mass energy with the CDF II detector at the Fermilab Tevatron collider. The measured value is in tension with the prediction of the model.

Friday 29 April 2022, 16:00: Louie Corpe (CERN)

The search for exotic long-lived particles: illuminating a blind spot of the LHC programme

Exotic long-lived particles (LLPs) occur in many well-motivated extensions to the Standard Model (SM) of particle physics, and could explain the nature of Dark Matter (DM). However, LLPs could have been missed by the traditional LHC search programme to date due to their non-standard energy deposition patterns, which would often be thrown away as noise by standard reconstruction techniques. LLP signatures could be hiding in the “Blind Spot” of LHC searches! This talk will include a general motivation for LLP searches, and highlight the sort of signatures which are expected at CMS and ATLAS, as well as the unusual background which must be mastered. Recent examples of LLP results from the ATLAS collaboration will be used to highlight some of the novel techniques which are employed in these searches. Finally, prospects for the development of the LLP programme at CERN in coming years will be presented.

Friday 25 March 2022, 10:00: IoP Practice Talks — E7/Zoom

IoP Practice Talks

Practice Talks for IoP Conference.

Friday 18 March 2022, 16:00: Sean Mee (Graz)

On the construction of theories of composite dark matter

The dark matter remains one of the most famous unanswered questions in physics today. Despite the popular weakly interacting massive particle (WIMP) paradigm, a new class of theories posits that dark matter could be described as the lightest bound state in a QCD-like confining hidden sector. We discuss the construction of theories which describe the interactions of these states with other interesting bound states of the hidden sector, with a particular focus on pseudoreal symmetry groups. We highlight the key differences between such theories and the more familiar SM QCD. We present some results for the low-energy quantities describing the spectrum of these composite theories (masses and decay constants). Finally, we discuss the simplest portals which could allow us to look for such sectors at colliders and elsewhere, the associated symmetry breaking patterns and the potential phenomenological consequences.

Wednesday 16 March 2022, 15:30: Prof. David Waters — Harrie Massey LT

XXXI Elizabeth Spreadbury Lecture: The Mystery of Neutrino Mass

We don't know the mass of the most abundant fermion in the universe. We suspect that the origin of neutrino masses might be quite different from those of other fundamental particles. The talk will begin with a review of what we know about neutrino mass and its generation. We will present experiments, some of which are UCL-led, that aim to determine the nature of neutrino mass. A crude neutrino mass measurement will be attempted during the lecture itself, before presenting a perspective on how this field may develop over the next few years.

Friday 11 March 2022, 16:00: Nicola McConkey (Manchester)

Latest results from MicroBooNE and the outlook for the SBN programme

The MicroBooNE experiment is a liquid argon neutrino detector making groundbreaking neutrino physics measurements in the BNB and NuMI beamlines at Fermilab. I will present the latest results from new physics searches and neutrino cross-section measurements with MicroBooNE, and the outlook for the future, with a particular view to the physics potential of the Short Baseline Neutrino programme at Fermilab.

Friday 04 March 2022, 16:00: Inwook Kim (LANL)

Results from Baksan Experiment on Sterile Transitions (BEST)

The Baksan Experiment on Sterile Transitions (BEST) was designed to investigate the deficit of electron neutrinos, ƞ_e, observed in previous gallium-based radiochemical measurements with high intensity neutrino sources, commonly referred to as the gallium anomaly. Based on the Gallium-Germanium Neutrino Telescope (GGNT) of the SAGE experiment, the BEST setup is comprised of two zones of liquid Ga target to explore neutrino oscillations on the meter scale. Any deficits in the ⁷¹Ge production rates in the two zones, as well as the differences between them, would be an indication of nonstandard neutrino properties at this short scale. From July 5th to October 23rd 2019, the two-zone target was exposed to the mainly monoenergetic ⁵¹Cr neutrino source ten times with 20 independent ⁷¹Ge extractions from the two Ga targets. The ⁷¹Ge decay rates were measured from July 2019 to March 2020 to determine the total production rate from the neutrino source. At the end of the experiment, the counting systems were calibrated using ⁷¹Ge isotope data taken in November 2020. We report the results from the BEST sterile neutrino oscillation experiment. 4σ deviations from unity were observed for the ratio of the measured ⁷¹Ge production rate to the predicted rate from the known cross section in both zones and confirm the previously reported Ga anomaly. If interpreted in the context of neutrino oscillations, the deficits give best fit oscillation parameters of Δm² = 3.3^+∞_-2.3 ~eV² and sin² 2θ = 0.42^+0.15_-0.17, consistent with ν_e → ν_s oscillations governed by a surprisingly large mixing angle.

Friday 25 February 2022, 16:00: Veronique Boisvert (RHUL)

The Climate Emergency: can Particle Physics ever be sustainable?

We live in a climate emergency and consequently all countries are putting in place measures to reduce their carbon emissions in order to reach a so-called “net zero emissions” by 2050. All aspects of economic life will be affected by such measures, including particle physics research. I will present some examples of sources of carbon emissions within the field of particle physics. This will include emissions associated with building and running accelerators, detector operations, high-performance computing and activities associated with our research life like travel. I will also present solutions being developed for addressing this in the near and long term as well as recommendations for the field.

Friday 18 February 2022, 16:00: Alexander Booth (Queen Mary)

Latest 3-flavour Oscillation Results form the NOvA Experiment

NOvA is a long-baseline neutrino oscillation experiment searching for electron neutrino appearance and muon neutrino disappearance. To do this, NOvA uses the NuMI beam at Fermi National Accelerator Laboratory along with two functionally identical detectors, separated by a baseline of 809 km. A near detector, which is close to the point of neutrino production, provides a measurement of initial beam energy spectra and flavour composition. The spectra are then extrapolated to a far detector and compared to data to look for oscillations. The experiment is able to constrain several parameters of the PMNS matrix and is sensitive to the neutrino mass hierarchy. This seminar presents a 3 flavour oscillation analysis of 6 years of NuMI data collected by the NOvA far detector corresponding to a 14 ktonne equivalent exposure of 3.60\times 10^{20}$ and 2.50\times 10^{20}$ protons on target, in neutrino and antineutrino beam modes respectively. The analysis, shown for the first time at the International Conference on Neutrino Physics and Astrophysics in 2020, builds on previous results with a new simulation, updated reconstruction and roughly 50\% more neutrino data.

Friday 11 February 2022, 16:00: Sunny Vagnozzi (Cambridge)

Terrestrial, cosmological, and astrophysical direct detection of dark energy

Most of the efforts in searching for dark energy, the component responsible for the accelerated expansion of the Universe, have focused on its gravitational signatures and in particular on constraining its equation of state: however, there is a lot to be learned about dark energy by getting off the beaten track. I will argue that non-gravitational interactions of dark energy with visible matter are natural and somewhat unavoidable, and lead to the possibility of direct

Friday 17 December 2021, 16:00: Mario Campenelli

Forward detectors in ATLAS

While most of the particles produced in LHC collisions are emitted in the forward detectors, most of the physics program and detectors focus on high-pt small-rapidity production. But the ATLAS experiment (as well as CMS) has several detectors aiming at measuring particles emitted very close to the beam, covering a large class of measurements, different and complementary to those performed with only the central detectors. In this seminar I will describe the forward detectors from ATLAS, their goals, their current status and their use in past and future physics measurements.

Friday 10 December 2021, 16:00: Elisabetta Pallante (Groningen)

Theory of the Muon g-2

I review the status of the theoretical prediction for the anomalous magnetic moment of the muon within the Standard Model of Particle Physics. Guided by a historical perspective, the seminar will cover physics and anecdotes from the first calculations to current efforts. I will discuss the challenges, strategies, status, and open questions of the Standard Model prediction. Is the discrepancy between the latter and current experimental results hinting at new physics?

Friday 26 November 2021, 16:00: Melissa van Beekveld (Oxford)

SUSY wanted - dead or alive

Due to the null-results at the LHC in the search for supersymmetry (SUSY), there is a growing belief that the concept of SUSY is just another failed theory. In this talk, we will examine where this belief comes from. We will take a careful look at the fine-tuning problem, and see that the story is a lot more nuanced than often suggested. If time allows, we will also discuss the dark side of SUSY.

Friday 19 November 2021, 16:00: Yoshi Uchida (Imperial)

CP-Violation: the next stop on our neutrino journey of discovery?

The field of neutrino oscillations has experienced several breakthrough moments over the past couple of decades, each time with a number of vastly different experiments coming together to point the way forward. The most recent breakthrough, from the T2K Experiment, shows that we are already able to start probing whether our description of neutrinos should include a significant CP-violating complex phase, something that even the most optimistic of us might not have bet too much on when we set out to build the experiment. As we enter a new era, with DUNE and Hyper-K—the next generation of very long-baseline experiments—well into construction, I will introduce the field of neutrino oscillations and our most recent results, how we got here and the challenges we face as we pursue the next breakthroughs that neutrinos have in store for us.

Friday 12 November 2021, 16:00: Clara Barker (Oxford)

Scattering atoms, electrons and perceptions

In this talk I will discuss the state of equity and inclusion in the UK in the field of STEM, with examples from my own journey. I will discuss why it is something we should consider, how science can benefit from making STEM more equitable, and suggest some thinking points for bring about this change.

Friday 28 May 2021, 16:00: Andy Buckley (Glasgow)

Accelerating physics impact: the why & how of Rivet analysis preservation

In a decade, the LHC experiments have issued over 3000 analysis papers, covering a huge spectrum of physics from soft QCD to myriad high-scale regions sensitive to hypothetical BSM physics. Central to the vast majority of these studies have been MC event generators, whose sophistication has also increased manyfold though the period of LHC operation. In this talk I'll review the ways in which the Rivet toolkit -- a key tool in this rise -- emerged from MC development and tuning, the development of its many hundreds of encoded analyses, through to its current leading-edge use as a powerful complement to BSM direct-searches in global fits of new physics. Whether your interest is QCD, electroweak, or BSM physics, I will show how the small amount of work in preparing a Rivet routine acts as a gateway to analysis re-use and greater physics impact.

Friday 21 May 2021, 16:00: Giovanni De Lellis (Naples)

Collider neutrinos: the SND@LHC experiment at CERN

SND@LHC is a compact and stand-alone experiment to perform measurements with neutrinos produced at the LHC in a hitherto unexplored pseudo-rapidity region of 7.2<𝜂<9.6, complementary to all the other experiments at the LHC. The experiment is to be located 480 m downstream of IP1 in the unused TI18 tunnel. The detector is composed of a hybrid system based on an 800 kg target mass of tungsten plates, interleaved with emulsion and electronic trackers, followed downstream by a calorimeter and a muon system. The configuration allows efficiently distinguishing between all three neutrino flavours, opening a unique opportunity to probe physics of heavy flavour production at the LHC in the region that is not accessible to ATLAS, CMS and LHCb. This region is of particular interest also for future circular colliders. The detector concept is also well suited to searching for Feebly Interacting Particles via signatures of scattering in the detector target. The first phase aims at operating the detector throughout LHC Run 3 to collect a total of 150 fb−1. The experiment was recently approved by the Research Board at CERN. A new era of collider neutrino physics is just starting.

Friday 14 May 2021, 16:00: Sneha Malde (Oxford)

Exploiting the strengths of the BESIII and LHCb experiments to make the most precise CKM angle gamma measurement

The BESIII and LHCb detectors – while both dedicated to flavour physics are different in collision energy, collision particle, geometry and size. Nonetheless in the quest to understand the Standard Model or potential new physics models they both play an important role. BESIII has the largest sample of quantum-correlated decays of the Psi(3770) meson – useful for measurement of the seemingly obscure charm strong-phase parameters. However, these are vital for studies at LHCb where their combination with the huge B decay samples leads to the most precise measurement of the CKM angle gamma. In this talk I will describe the significant developments over the last 18 months in this sector and discuss the leading measurements at both experiments.

Friday 07 May 2021, 16:00: Mitesh Patel (Imperial)

Update on the B-anomalies

I will give an update on the so-called B-anomalies, focussing on the recent evidence for lepton flavour universality breaking from the LHCb experiment.

Friday 30 April 2021, 16:00: Liz Kneale (Sheffield)

WATCHMAN: Project Overview and New Techniques for Reactor Antineutrino Detection

Monitoring known nuclear reactors and identifying an unknown nuclear reactor in a complex nuclear landscape is challenging. WATCHMAN will demonstrate for the first time a scalable anti-neutrino detector for mid- to far-field nuclear non-proliferation applications. In this talk, I will discuss the nuclear power-weapons connection and the proposed WATCHMAN anti-neutrino detector and remote reactor monitor prototype, before going on to show how using new and updated reconstruction and analysis methods can improve anti-neutrino signal detection and background suppression to optimise the sensitivity of Gd-doped water Cherenkov detection for remote reactor monitoring.

[recording]

Friday 23 April 2021, 16:00: Paolo Franchini (Imperial)

The Muon Ionization Cooling Experiment and the muon ionization cooling demonstration

Future muon colliders can study lepton-antilepton collisions up to several TeV while neutrino beams produced in neutrino factories from stored beams will have an unique precision in measuring neutrino oscillations. Both muon colliders and neutrino factories will require intense muon sources with low emittance. Muons produced from decays of pions (created in proton-target interactions) occupy a large phase space which makes difficult the acceleration and storage of the beam. Cooling techniques like stochastic cooling (successfully used for protons at CERN) do not prove to be efficient methods due to the short lifetime of the muons. Ionization cooling, proposed in the late '60s and only recently demonstrated by MICE (Muon Ionization Cooling Experiment) consists in reducing the amplitude of the muon beams, passing the muons through an absorber in order to remove part of the transverse and longitudinal momenta, eventually restoring the longitudinal component with radiofrequency cavities. The result is a reduction of the transverse emittance which can be traduced as an increase of the phase space density. In the present talk I will introduce MICE, describe the recent results and outline possible future scenarios.

[recording]

Friday 16 April 2021, 16:00: Kristin Lohwasser (Sheffield)

Photon collisions at the LHC: Probing the electroweak sector

The observation of WW production in photon collisions, yy->WW, represents a mile stone in the quest to fully characterize the electroweak sector of the SM. The talk will discuss the details of this challenging measurement: Origin of photons at the LHC, treatment of pile-up and the modelling of the signal as well as that of the underlying event for background processes. An outlook on how this will play a role for future tests of the Standard Model and in searches of new physics at the TeV scale is given.

[recording]

Friday 19 March 2021, 16:00: John Nugent (Glasgow)

WAGASCI: A New Near Detector at T2K

WAGASCI is a newly installed detector at the J-PARC facility and part of the T2K experiment. Located at the end of the neutrino beam line it provides measurements of the neutrino flux before oscillation. Its design is fundamentally different from the existing near detectors and offers the first opportunity to measure the ratio of neutrino cross-sections on water and hydrocarbon to within a total uncertainty of 3%. This will allow neutrino nuclear scattering to be probed to a never before achievable extent. Developing our understanding of neutrino nuclear interactions is critical to the future of T2K and the long baseline neutrino program in general. Only through understanding these interactions can T2K reached the desired sensitivity to CP violation in leptons. A measurement of CP violation in neutrino oscillation would constitute one of the most significant breakthroughs in the field of particle physics for decades. In this seminar the WAGASCI detector will be introduced and the status after its first commissioning and physics runs reported.

[recording]

Friday 19 February 2021, 16:00: Jost Migenda (Kings College London)

The Hyper-Kamiokande Experiment

Hyper-Kamiokande is a next generation neutrino and nucleon decay experiment that is expected to start taking data in 2027. In this talk, I will introduce the experiment and current construction progress. I will then give an overview over its broad physics programme, with a special focus on neutrino astronomy.

[recording]

Friday 05 February 2021, 16:00: Ben Kilminster (UZH)

Probing 10 orders of magnitude of dark matter mass using CCDs: New results from DAMIC@SNOLAB and prospects for DAMIC-M

"The DAMIC (Dark Matter in CCDs) experiment uses CCD detectors to search for the direct interaction of galactic dark matter. Scientific CCD detectors provide an unprecedented low energy threshold and spatial resolution to probe for light dark matter. Given the current lack of evidence for a WIMP of mass around the weak scale, DAMIC focuses its search on lighter WIMPs, as well as the interaction of hidden-sector photons that could mediate the interaction of DM or even comprise DM. The current experiment, DAMIC@SNOLAB pioneered the search for hidden-photon interactions of DM and set world-leading constraints for low-mass WIMPs with a silicon-based target. The next experiment, DAMIC-M at LSM (Laboratoire Souterrain de Modane in France) will be sensitive to never-before probed potential DM models, covering a broad range of models spanning from eV to 10 TeV. In this talk, exciting new results from DAMIC@SNOLAB and prospects from DAMIC-M will be presented."

Friday 29 January 2021, 16:00: Artur Sztuc (UCL)

Recent neutrino oscillation results from the T2K experiment

T2K is a long baseline neutrino experiment using a beam of mostly muon neutrinos from the Japan Particle Accelerator Research Centre in Japan, and measuring their oscillated state 295 km away in the Super-Kamiokande detector.  Measuring the change in the neutrino flavour at Super-Kamiokande constrains the neutrino oscillation parameters of the PMNS matrix, specifically Δm232, sin2 θ23 and the CP-violating phase ΔCP. The 2019 results from T2K have shown a strong constraint on ΔCP, with large regions of ΔCP excluded at 3σ CL. This talk will describe results from T2K with the data collected until early 2020, and the future prospects for the experiment.

[slides]

Friday 15 January 2021, 16:00: Martin Slezak (Max Planck Inst.)

First neutrino mass results from the KATRIN experiment

Knowledge of the absolute neutrino mass scale is of particular importance to particle physics, astrophysics and cosmology. The Karlsruhe Tritium Neutrino (KATRIN) experiment aims to search for the effective electron antineutrino mass with an unprecedented sensitivity of 200 meV from the shape of tritium beta-decay spectrum near its kinematical endpoint. In 2019 KATRIN performed the first measurement yielding a new upper limit of 1.1 eV (90 % C.L.) for the neutrino mass using beta-decay. In this talk, I will give an overview of the KATRIN experiment and discuss the first neutrino mass campaign in detail. I will also briefly mention perspectives for the next measurement which took place in 2020 and is currently under analysis.

[recording]

Friday 11 December 2020, 16:00: Jens Weingarten (Dortmund)

A Second Life - ATLAS Pixel Detectors in Medical Physics

The field of medical physics has been growing steadily over the past decades, with more and more hospitals using more and more complex machinery in diagnosis and treatment of patients. Reacting to the increased demand for well-trained medical physics experts, TU Dortmund university offers a medical physics study programme since 2011. Close collaborations with hospitals and dedicated centers for radiotherapy and proton therapy open up a great many possibility for the resident HEP detector physicists to find new applications for our well-known technologies. Coming from the development of silicon pixel detectors for the ATLAS tracking detector, we started looking into applications where those detectors could be useful. These range from beam monitoring for machine QA for proton therapy, via small-field dosimetry to proton radiography and proton CT. In the talk I will report on some of our activities, as well as some future developments.

[recording]

Friday 27 November 2020, 16:00: Juan Miguel Carceller (UCL)

Ultra-High Energy Cosmic Rays with the Pierre Auger Observatory

Even though cosmic rays were discovered more than one hundred years ago, there are still many questions unanswered about them. Some of them reach energies that are macroscopic (above 10^18 eV or .16 J). What are they? What is their origin? How are they accelerated to such energies? To answer these questions the Pierre Auger Observatory was built. It comprises more than 1600 surface detector that measure the arrival time and signal left by secondary particles of air showers, initiated when of these cosmic rays collides with a molecule of air in the atmosphere. The array of surface detector is overlooked by fluorescence telescopes that measure the fluorescence light emitted. I will introduce cosmic rays, the air showers that they produce and how the Pierre Auger Observatory measures them. A few recent results on composition and hadronic interactions will be shown, and some of my contributions to these topics.

[slides]

Friday 20 November 2020, 16:00: Thorben Quast (RWTH)

The CMS High Granularity Calorimeter upgrade for HL-LHC

The CMS collaboration is preparing to build replacement endcap calorimeters for the HL-LHC era. The new calorimeter endcap will be a highly-granular sampling calorimeter (HGCAL) featuring unprecedented transverse and longitudinal readout segmentation for both its electromagnetic and hadronic compartments. The granularity together with a foreseen timing precision on the order of a few tens of picoseconds will allow for measuring the fine structure of showers, will enhance pileup rejection and particle identification, whilst still achieving good energy resolution. The regions exposed to higher-radiation levels will use silicon as active detector material. The lower-radiation environment will be instrumented with scintillator tiles with on-tile SiPM readout. In addition to the hardware aspects, the reconstruction of signals, both online for triggering and offline, represents a challenging task - one where modern machine learning approaches are well applicable. In this talk, the reasoning and ideas behind the HGCAL, the proof-of-concept of its design in test beam experiments, and the challenges ahead will be presented.

[recording]

Friday 30 October 2020, 16:00: Sarah Malik (UCL)

Quantum computing for simulating high energy collisions

The simulation of high energy collisions at experiments like the Large Hadron Collider (LHC) relies on the performance of full event generators and their accuracy and speed in modeling the complexity of multi-particle final states. The rapid improvement of quantum devices presents an exciting opportunity to construct dedicated algorithms to exploit the potential quantum computers can provide. I will present general and extendable quantum computing algorithms to calculate two key stages of an LHC collision; the hard interaction via helicity amplitudes and the subsequent parton shower process. These algorithms fully utilise the quantum nature of the calculations and the machine's ability to remain in a quantum state throughout the computation. It is a first step towards a quantum computing algorithm to describe the full collision event at the LHC.

Friday 23 October 2020, 16:00: Julieta Gruszko (UNC)

Shedding ‘Nu’ Light on the Nature of Matter: NuDot and the Search for Majorana Neutrinos

Why is the universe dominated by matter, and not antimatter? Neutrinos, with their changing flavors and tiny masses, could provide an answer. If the neutrino is its own antiparticle, it would reveal the origin of the neutrino’s mass, demonstrate that lepton number is not a conserved symmetry of nature, and provide a path to leptogenesis in the early universe. To discover whether this is the case, we must search for neutrinoless double-beta decay. As the upcoming ton-scale generation of experiments is built, it is key that research and development (R&D) efforts continue to explore how to extend experimental sensitivities to 1029 years and beyond. These next-next-generation experiments could make a discovery, if neutrinoless double-beta decay is not found at the ton-scale, or offer insight into the mechanism behind lepton number violation, if it is. NuDot is a proof-of-concept liquid scintillator experiment that will explore new techniques for isotope loading and background rejection in future detectors. I’ll discuss the progress we’ve already made in demonstrating how previously-ignored Cherenkov light signals can help us distinguish signal from background, and the technologies we’re developing with an eye towards the coming generations of experiments.

[recording]

Friday 31 July 2020, 16:00: Chris Young (CERN)

Testing lepton flavour universality

[recording]

Friday 19 June 2020, 16:00: Susanne Westhoff (Heidelberg)

Co-scattering dark matter at the LHC

In this talk I will show how to search for feebly coupled dark matter at the LHC. If dark matter freezes out through co-annihilation or co-scattering in the early universe, the observed relic abundance predicts a clear signature at colliders: soft displaced objects. I will present a strategy to search for soft displaced leptons at the LHC during Runs 2+3.

[recording]

Friday 05 June 2020, 16:00: Anna Sfyrla (Geneva)

FASER

The FASER experiment is a new small and inexpensive experiment that will be placed 480 meters downstream of the ATLAS experiment at the CERN LHC. The experiment will shed light on currently unexplored phenomena, having the potential to make a revolutionary discovery. FASER is designed to capture decays of exotic particles, produced in the very forward region, out of the ATLAS detector acceptance. FASERnu, a newly proposed FASER sub-detector, is designed to detect collider neutrinos for the first time and study their properties. This talk will present the physics prospects, the detector design, and the construction progress of FASER. The experiment is expected to be installed in 2020 and to take data during the LHC Run-3, starting in 2021.

[recording]

Friday 29 May 2020, 16:00: Stefan Schoernert (TUM)

LEGEND

The Large Enriched Germanium Experiment for Neutrinoless Double-Beta Decay

[recording]

Friday 22 May 2020, 16:00: Robert Thorne (UCL)

Inferring the effective fraction of the population already infected with Covid-19 by comparing rates in different regions of the same country

I use a very simple deterministic model for the spread of Covid-19 in a large population. Using this to compare the relative decay of the number of deaths per day between different regions in Italy, Spain and England, each applying in principle the same social distancing procedures across the whole country, I obtain an estimate of the total fraction of the population which has already become infected. In the most heavily affected regions, Lombardy, Madrid and London, this fraction is higher than expected, i.e. ~ 0.3. This result can then be converted to a determination of the infection fatality rate ifr, which appears to be ifr ~ 0.0025-0.005, and even smaller in London, somewhat lower than usually assumed. Alternatively, this can also be interpreted as a effectively larger fraction of the population than simple counting would suggest if there is a variation in susceptibility to infection with a variance of up to a value of about 2. The implications are very similar for either interpretation or for a combination of effects.

[slides]

Friday 15 May 2020, 16:00: Matthias Becker (Dortmund)

The Neutrino Portal To Dark Matter

If Dark Matter is an electroweak gauge singlet, it cannot interact with the standard model via these interactions, thereby requiring the existence of so-called portal couplings. The three renormalizable portal couplings are the Higgs portal, the vector portal, and the neutrino portal. In this talk, we investigate the neutrino portal to Dark Matter and inspect the viable production mechanisms and different constraints on the resulting parameter space.

[recording]

Friday 24 April 2020, 16:00: Ioannis Katsioulas (Birmingham)

Search for Light dark matter with Spherical Proportional Counters

[recording]

Friday 10 April 2020, 16:00: EASTER

No seminar

Friday 03 April 2020, 16:00: IOP Practice TALKS

IoP Practice talks

TBC

Friday 27 March 2020, 16:00: Kirsty Duffy (FNAL)

Latest neutrino cross-section results from MicroBooNE

MicroBooNE, the Micro Booster Neutrino Experiment at Fermilab, is an 85-ton active mass liquid argon time projection chamber (LArTPC) located in the Booster Neutrino Beam at Fermilab. The LArTPC technology with 3mm wire spacing enables high-precision imaging of neutrino interactions, which leads to high-efficiency, low-threshold measurements with full angular coverage. As the largest liquid argon detector worldwide taking neutrino beam data, MicroBooNE provides a unique opportunity to investigate neutrino interactions in neutrino-argon scattering at O(1 GeV) energies. These measurements are of broad interest to neutrino physicists because of their application to Fermilab's Short Baseline Neutrino program and the Deep Underground Neutrino Experiment (which will both rely on LArTPC technology), as well as the possibility for new insights into A-dependent effects in neutrino scattering on heavier targets such as argon. In this seminar I will present the most recent cross-section results from MicroBooNE, including measurements of inclusive charged-current neutrino scattering, neutral pion production, and low-energy protons. Many of the results I will show represent the first measurements of these interactions on argon nuclei, as well as an exciting demonstration of the potential of LArTPC detector technology to improve our current understanding of neutrino scattering physics.

[recording]

Friday 20 March 2020, 16:00: Theresa Fruth (UCL)

Searching for Dark Matter with the LZ experiment

The nature of dark matter remains one of the biggest mysteries of the universe. Extensions to the Standard Model of particle physics provide potential candidates for it. Such dark matter particles can be searched for using direct detection experiments. The LUX-ZEPLIN (LZ) experiment is a next-generation direct detection experiment, which employs a two-phase, liquid xenon time projection chamber. It is currently under construction 4850 feet underground in an old gold mine in South Dakota. In this talk I will give an overview of the experiment and its projected sensitivity reach, as well as the current status of construction and integration.

Friday 13 March 2020, 16:00: Susanne WestHoff (Heidelberg) POSTPONED

Dark matter searches with long-lived particles POSTPONED

In cosmological scenarios beyond thermal freeze-out dark matter interactions with standard-model particles can be tiny. This leads to mediators with a lifetime that is long compared with the scales of particle colliders. In this talk I will discuss two new ideas for collider searches with long-lived mediators: soft displaced objects as signs of compressed dark sectors at the LHC; and displaced vertices from long-lived light scalars at flavor and long-distance experiments. I will show that novel search strategies allow us to explore dark matter interactions ranging over several orders of magnitude.

Friday 06 March 2020, 16:00: Alex Martyniuk (UCL)

Recent results from the LHC

Between 2015 to 2018 (a.k.a. Run 2) the LHC delivered around 160fb^-1 to both of its general purpose detectors: ATLAS and CMS. In this talk I will try to roughly outline what the experiments have done so far with this bounty of data, and where they are headed in the future. (This talk was previously given as the opening talk of the Lake Louise Winter Institute).

[slides]

Friday 14 February 2020, 16:00: Ilektra Christidi (UCL)

Research Software Development at UCL and the software landscape in HEP

With computing and large amounts of data becoming more and more an everyday reality in all research domains, the world is waking up to what High Energy Physicists knew all along: software is an integral part of research, and as such, it is a necessity to have the infrastructure and people to support its sustainable development. The UCL Research Software Development Group, a centralised service for the whole university research community, and the first group of its kind in the UK, has been here since 2012 to serve exactly this purpose. In the first part of this talk, I'll introduce the scope and work of our group, and will try to identify (with your help!) ways that we can be of service to the UCL HEP researchers. In the second part, I'll present a review of the latest PyHEP workshop, a forum where developments in the use of Python in Particle Physics are presented.

Friday 07 February 2020, 16:00: Katharina Behr (DESY)

The puzzle of dark matter: missing pieces at the LHC?

Unravelling the particle nature of dark matter is one of the key goals of the LHC physics programme. Dark matter cannot be detected directly by the LHC experiments but would manifest itself as missing energy in the detector signature of collision events. Complementary resonance searches targeting new mediator particles between dark and known matter provide an additional approach to explore the interactions of dark matter. To date, no evidence for dark matter or related mediators has been found. Could dark matter interactions be more complex or have otherwise have evaded detection? I will review the diverse programme of dark matter searches on LHC Run 2 data and address strategies to extend our coverage of possible dark matter signatures at the LHC.

Friday 31 January 2020, 16:00: Tevong You (Cambridge)

Where art thou, new physics?

Searching for new fundamental physics beyond the Standard Model, by experimenting, observing and theorising, is a tremendously exciting journey. One of our most reliable guides in this voyage of exploration is the framework of effective field theory. Through this lens, I will survey the landscape of where new physics may be hiding, from electroweak precision observables, diboson, Higgs, and flavour physics to light dark sectors. I conclude with the question of what, if anything, could we ultimately discover at future colliders?

Friday 24 January 2020, 16:00: POSTPONED till 14.02.

Enjoy cake and puppies instead

TBC

Friday 13 December 2019, 16:00: Jessica Turner (FNAL)

Neutrino masses from gravity

In this talk I will discuss neutrino masses in general and demonstrate that non-zero neutrino masses can be generated from gravitational interactions. In this work we solve the Schwinger-Dyson equations to find a non-trivial vacuum thereby determining the scale of the neutrino condensate and the number of new particle degrees of freedom required for gravitationally induced dynamical chiral symmetry breaking. We show for minimal beyond the Standard Model particle content, the scale of the condensation occurs close to the Planck scale.

[slides]

Friday 06 December 2019, 16:00: Tevong You (Cambridge) — CANCELED!

TBC

TBC

Friday 29 November 2019, 16:00: Ilektra Christidi (UCL) — CANCELED!!

Research Software Development Group

TBC

Friday 22 November 2019, 16:00: Lucas Lombriser (Geneva)

Towards Understanding the Cosmic Expansion at Late Times

I will first discuss how recent gravitational wave measurements have brought the predicted challenges to explaining cosmic acceleration by a modification of General Relativity as alternative to the cosmological constant. In a second part, I will describe a possible solution of the cosmological constant problem. I will show how interpreting the Planck mass in the Einstein-Hilbert action as a global Lagrange multiplier prevents vacuum energy from gravitating and with account of the inhomogeneous cosmic small-scale structure predicts an energy density parameter of the cosmological constant of 0.704, in good agreement with observations. Finally, I will argue that there is no Hubble tension. Rather, the discrepant measurements imply that we are located in a 50% underdense 40 Mpc region of the Cosmos, within cosmic variance and in good agreement with the measured local distributions of galaxies and clusters.

Friday 08 November 2019, 16:00: Raffaella Radogna (UCL)

A calorimeter for particle therapy range verification

Particle beam therapy provides significant benefits over conventional X-ray radiotherapy. Protons and heavier ions lose most of their energy in the last few millimetres of their path (Bragg Peak), enabling tumours to be targeted with greater precision and reducing the collateral damage to surrounding healthy tissue. An important challenge in particle therapy is the uncertainty in the range of the beam. To ensure that treatment is delivered safely, a range of quality assurance (QA) procedures are carried out each day before treatment starts. A detector is currently under development at University College London to provide fast and accurate proton range verifications, and speed up the daily QA process. The new system utilises a multi-layer calorimeter to record the depth-dose distribution of a proton therapy treatment beam and make direct measurements of the Water Equivalent Path Length (WEPL) with high resolution at clinical rates. The range calorimeter is also used to test the achievable sensitivity of real-time theranostics for carbon treatment using a mixed He/C beam. Range uncertainties caused by intra-fractional motion during carbon ion treatment could be monitored online using a small contamination of helium ions in the beam. At the same energy per nucleon, helium ions have about three times the range of carbon ions, which could allow, for certain tumours, a simultaneous use of the carbon beam for treatment and the helium beam for imaging. In this talk, the design and performance of the Quality Assurance Range Calorimeter (QuARC) are presented.

Friday 01 November 2019, 14:00: Sarah Heim (DESY): UNUSUAL TIME and PLACE: Physics E7

Higgs differential cross section measurements in the H->ZZ*->4l decay channel with the ATLAS detector.

One of the most promising approaches for probing Higgs boson production and decays are differential cross sections. Measuring the Higgs boson transverse momentum and other distributions can shed lights on the couplings of different Standard Model particles to the Higgs boson. I will discuss fiducial and differential cross section measurements in the H->ZZ*->4l decay channel, often called the golden channel, and highlight the important role of lepton reconstruction and identification. Furthermore I will discuss a number of interpretations and give an outlook for Higgs differential cross section measurements at the High-Luminosity LHC.

[slides]

Friday 25 October 2019, 16:00: Katharina Behr (DESY) — CANCELED!

The puzzle of dark matter: missing pieces at the LHC

Unravelling the particle nature of dark matter is one of the key goals of the LHC physics programme. Dark matter cannot be detected directly by the LHC experiments but would manifest itself as missing energy in the detector signature of collision events. Complementary resonance searches targeting new mediator particles between dark and known matter provide an additional approach to explore the interactions of dark matter. To date, no evidence for dark matter or related mediators has been found. Could dark matter interactions be more complex or have otherwise have evaded detection? I will review the diverse programme of dark matter searches on LHC Run 2 data and address strategies to extend our coverage of possible dark matter signatures at the LHC.

Friday 18 October 2019, 16:00: Ralf Kaiser (Glasgow)

Cosmic Ray Muography

Muons are fundamental, charged particles that form part of our naturally-occurring background radiation. They are produced in particle showers in the upper atmosphere from the impact of cosmic rays. These muons are incident at sea-level at a rate of about one per square centimetre per minute and with average energies of about 3 GeV - approximately four orders of magnitude more than typical X-rays. Muons are highly penetrating and can traverse hundreds of metres of rock, which has opened up the possibility to use them for challenging imaging applications. Muography is an established technique in volcanology, it has been used to find a cavity in the pyramid of Khufu in Egypt and over the last years a wide variety of applications have been explored – ranging from cargo screening to nuclear waste characterisation and carbon storage monitoring. Lynkeos Technology is a spin-out company from the University of Glasgow, founded in 2016 following a 7-year, £4.8M research programme funded by the NDA. The Lynkeos Muon Imaging System is the worldwide first, CE-marked muon imaging system for the characterization of nuclear waste containers. It has been successfully deployed on the Sellafield site in October 2018. This talk will give an overview of muography applications worldwide and present the activities of Lynkeos Technology in detail, with a focus on the characterization of nuclear waste containers.

[slides]

Monday 14 October 2019, 16:00: Nivedita Ghosh (IACS Kolkata)

Associated $Z^\prime$ production in the flavorful $U(1)$ scenario for $R_{K^{(*)}}$

The flavorful $Z^\prime$ model with its couplings restricted to the left-handed second generation leptons and third generation quarks can potentially resolve the observed anomalies in $R_K$ and $R_{K^*}$. After examining the current limits on this model from various low-energy processes, we probe this scenario at 14 TeV high-luminosity run of the LHC using two complementary channels: one governed by the coupling of $Z'$ to $b$-quarks and the other to muons. We also discuss the implications of the latest LHC high mass resonance searches in the dimuon channel on the model parameter space of our interest.

Friday 20 September 2019, 16:00: Yanhui Ma (UCL)

Observation of H-->bb decays and VH production with the ATLAS detector

A search for the decay of the Standard Model Higgs boson into a bb pair when produced in association with a W or Z boson is performed with the ATLAS detector. The analysis of 13 TeV data collected by ATLAS during Run 2 of the LHC in 2015, 2016 and 2017 leads to a significance of 4.9σ – alone almost sufficient to claim observation. This result was combined with those from a similar analysis of Run 1 data and from other searches by ATLAS for the H→bb decay mode, namely where the Higgs boson is produced in association with a top quark pair or via a process known as vector boson fusion (VBF). The significance achieved by this combination is 5.4σ.

[slides]

Friday 13 September 2019, 16:00: Evan Grohs (Berkeley)

Neutrino dynamics in big bang nucleosynthesis

The laboratory of the early universe provides a setting for testing Beyond Standard Model (BSM) physics in the particle and cosmological sectors. Any BSM physics in operation at early times may produce slight deviations in the primordial element abundances and cosmic microwave background observables predicted within the standard cosmology. The identification and characterization of such BSM signatures require a precise numerical treatment of the neutrino energy and flavor wave functions when the neutrinos decouple from the electromagnetic plasma. This weak decoupling process occurs during Big Bang Nucleosynthesis (BBN) and we employ Quantum Kinetic Equations (QKEs) to follow the out-of-equilibrium neutrino evolution. I will give an overview on the role neutrinos play in BBN, as well as give an introduction to the full QKE problem with neutrino oscillations and collisions. A QKE treatment of early-universe neutrino physics will greatly assist observers and theorists as the next-generation-cosmological experiments come on line in the near future.

[slides]

Monday 19 August 2019, 16:00: Jon Butterworth (UCL)

Highlights from EPS HEP 2019

I gave the highlights talk for this year's EPS meeting in Ghent and will repeat it for anyone in the group who is around and interested.

Monday 22 July 2019, 16:00: Alfredo Galindo-Ubarri (Oak Ridge National Laboratory) — Harry Massey Lecture Theatre

Neutrino Physics Opportunities at ORNL

The Physics Division at ORNL is exploring key opportunities for neutrino physics and supporting the formation of an experimental program at the intersection of particle, nuclear, and astrophysics. The Spallation Neutron Source (SNS) and the High Flux Isotope Reactor (HFIR) of ORNL are two very powerful neutrino sources that open new physics opportunities. Two new experiments, PROSPECT and COHERENT, make use of these unique capabilities and enable us to broaden the understanding of neutrino properties. PROSPECT consists of segmented 6Li-loaded liquid scintillator antineutrino detectors designed to probe short-baseline neutrino oscillations and precisely measure the reactor antineutrino spectrum. The COHERENT collaboration aims to measure CEvNS (Coherent Elastic Neutrino-Nucleus Scattering) at the SNS. The CEvNS process is cleanly predicted in the Standard Model and its measurement provides a Standard Model test. I will present a novel neutrino experiment which consists of a differential measurement of coherent-elastic neutrino-nucleus scattering using isotopically enriched Ge detectors. I will review some of the current activities taking place at ORNL including the development of ultrasensitive analytical techniques to detect trace elements of interest for neutrinoless double beta decay experiments and will present recent results.

[slides]

Thursday 18 July 2019, 16:00: Alex Keshavarzi (Fermilab)

The Muon g-2: theory and experiment

The study of the muon g-2 stands as an enduring and stringent test of the Standard Model (SM), where the current 3.5 standard deviations (or higher) discrepancy between the theoretical prediction and the experimental measurement could be an indication of new physics beyond the SM. The precision of the SM prediction is limited by hadronic contributions and, therefore, the Muon g-2 Theory Initiative are working hard to improve the SM evaluation in time for the next experimental result. In tandem, the Muon g−2 experiment at Fermilab is set to measure the muon anomaly with a four-fold improvement in the uncertainty with respect to previous experiment, with an aim to determine whether the g−2 discrepancy is well established. The experiment recently completed its first physics run and a summer programme of essential upgrades, before continuing on with its experimental programme. The Run-1 data alone are expected to yield a statistical uncertainty of 350 ppb and the publication of the first result is expected in late-2019. In this talk, I will discuss the advances in both the theoretical and experimental determinations of the muon magnetic anomaly, placing focus on my own evaluations of the hadronic vacuum polarisation contributions to the Muon g-2 and my current contributions to the Muon g-2 experiment at Fermilab.

[slides]

Friday 07 June 2019, 16:00: Fabon Dzogang (ASOS)

TBC

TBC

Friday 31 May 2019, 16:00: Erika Catano-Mur (William and Mary)

Recent results and outlook for the NOvA neutrino experiment

NOvA is a long-baseline neutrino oscillation experiment, which consists of two finely-segmented liquid-scintillator detectors operating 14 mrad off-axis from Fermilab’s NuMI muon neutrino beam. With an 810 km baseline, the measurements of muon neutrino disappearance and electron neutrino appearance allow the determination of neutrino oscillation unknowns, namely the mass hierarchy, the octant of the largest neutrino mixing angle, and the CP violating phase. In this talk, I will present the latest results of the NOvA oscillation analyses from four years of data taking, and discuss the experiment’s projected sensitivity to determine the mass hierarchy and to discover CP violation in the neutrino sector in future analyses with increased exposure.

[slides]

Friday 24 May 2019, 16:00: Peter Wijeratne (UCL)

From the Higgs to Huntington's: methods for learning from data

With the advent of datasets of unprecedented size and dimensionality in both physics and medicine, there is high demand for new methodologies that can extract hidden or obscured information. This is particularly important in ill-posed problems - such as the reconstruction of particles from detector interactions - and in problems with non-informative priors, which occur frequently in biological processes. In this talk I will give a high level view of the types of computational methods used to tackle these problems at the UCL Centre for Medical Image Computing, with a particular focus on Bayesian methods and unsupervised machine learning. I will also discuss how my previous research on ATLAS led to my current research in computational modelling of Huntington's disease, a devastating neurological condition that computational methods are shining new light on.

[slides]

Friday 17 May 2019, 16:00: Kate Scholberg (Duke)

Coherent elastic neutrino-nucleus scattering

Coherent elastic neutrino-nucleus scattering (CEvNS) is a process in which a neutrino scatters off an entire nucleus at low momentum transfer, and for which the observable signature is a low-energy nuclear recoil. It represents a background for direct dark matter detection experiments, as well as a possible signal for astrophysical neutrinos. Furthermore, because the process is cleanly predicted in the Standard Model, a measurement is sensitive to beyond-the-Standard-Model physics, such as non-standard interactions of neutrinos. The process was first predicted in 1973. It was measured for the first time by the COHERENT collaboration using the high-quality source of pion-decay-at-rest neutrinos from the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory and a CsI[Na] scintillator detector. This talk will describe COHERENT's recent measurement of CEvNS, the status and plans of COHERENT's suite of detectors at the SNS, and future physics reach. I will also cover prospects for supernova neutrino detection if time permits.

Friday 10 May 2019, 16:00: Monika Wielers (RAL)

HL-LHC and HE-LHC physics prospects

The Large Hadron Collider (LHC) has been successfully delivering proton-proton collision data at a centre of mass energy of 13 TeV. An upgrade is planned to increase the instantaneous luminosity delivered by the LHC by a factor of 5-7 (HL-LHC) for running in 2026 and beyond and there is also another possible future upgrade considered for running at an energy of 27 TeV at the high-energy LHC (HE-LHC). In the last 1.5 years, the LHC experiments prepared a CERN Yellow Report which summarises the physics reach for HL-LHC and HE-LHC and serves as input to the European Strategy this year. This talk shows highlights of the physics reach at the HL-LHC and HE-LHC detailed in the report. The physics prospects are shown for Higgs couplings measurements, di-Higgs boson production sensitivity, Vector Boson Scattering prospects as well as the discovery potential for electroweak SUSY and other exotic benchmark scenarios.

Friday 03 May 2019, 16:00: NO SEMINAR

NO SEMINAR

Friday 26 April 2019, 16:00: Sudan Paramesvaran (Bristol)

The CMS Trigger: Through the Ages

A trigger represents a fundamental component of hadron collider experiments. The ability to separate signal from background on extremely short time-scales represents a major technological and intellectual challenge. This seminar will seek to explain how the trigger system for the CMS Experiment at the LHC has evolved from the first run (2010 - 2012) through to its first major upgrade in 2016, where a significantly more advanced trigger was deployed. The focus will be on discussing custom electronics, architecture choices, and ultimate performance. With preparations well underway for High Luminosity LHC, the challenges and status of the next major overhaul of the trigger system will be also be described.

[slides]

Friday 19 April 2019, 16:00: EASTER FRIDAY

NO SEMINAR

TBC

Friday 12 April 2019, 16:00: Zara Grout (UCL)

A detector-corrected ATLAS measurement of four leptons designed for re-interpretation

This recently published analysis is at the forefront of designing precision measurements using the ATLAS detector which are sensitive to new physics. Traditional ATLAS searches provide maximally sensitive results on specific models with a fast turnaround using highly optimised event selections. I will discuss how these searches can be complemented by detector-corrected measurements which have a long shelf-life and can be used to search for Beyond the Standard Model scenarios by those within and external to the collaboration. In this instance the invariant mass spectrum of four leptons is shown to provide insight into a number of Standard Model processes and BSM scenarios.

[slides]

Friday 05 April 2019, 16:00: Preema Rennee Pais (EPFL)

'The LHCb detector upgrades, and prospects for rare decays and LFU measurements'

The LHCb detector is a single-arm forward spectrometer, designed to study decays of hadrons containing beauty and charm quarks. A major upgrade of the experiment is being performed during the ongoing LHC long shutdown 2. The upgraded detector will operate at an instantaneous luminosity five times higher than in Run 2. It can be read out at the full LHC bunch-crossing frequency of 40 MHz, enabling the use of a flexible software trigger system. The high luminosity LHC could provide peak luminosities of up to $2 \times 10^{34$} cm$^{-2}$ s$^{-1}$ to LHCb, about an order of magnitude above Upgrade I conditions. The collaboration is planning an Upgrade II detector, to be installed during long shutdown 4 of the LHC (2030), which will enhance sensitivity to a wide range of physics signatures. In this talk, I will present an overview of the Upgrade I detectors, and highlight detector design options and recent R&D to meet the challenge of real-time reconstruction in the HL-LHC environment. The talk will conclude with a discussion of the outlook for measurements of rare decays of $b$-hadrons and tests of lepton flavour universality with the upgrade datasets.

Friday 29 March 2019, 16:00:

IoP practce talks

TBC

Friday 22 March 2019, 16:00: TBC

TBC

TBC

Friday 15 March 2019, 16:00: Sebastian Trojanowski (Sheffield)

Looking forward to new physics with FASER: ForwArd Search ExpeRiment at the LHC

One of the most rapidly developing areas of research in particle physics nowadays is to look for new, light, extremely weakly-interacting particles that could have avoided detection in previous years due to the lack of luminosity. These, so-called intensity frontier searches, have also broad cosmological connections to e.g. dark matter, as well as can help to unravel the mystery of neutrino masses. In this talk, we will summarize the current status of this field with a particular emphasis on a newly proposed experiment to search for such particles produced in the far-forward region of the LHC, namely FASER, the ForwArd Search ExpeRiment. FASER has been proposed as a relatively cheap detector to supplement traditional experimental programmes searching for heavy new physics particles in the high-pT region and, therefore, to increase the whole BSM physics potential of the LHC. On top of potentially far-reaching implications to BSM particle physics and cosmology, the newly proposed detector can also be used to measure high-energy SM neutrino cross sections.

[slides]

Friday 08 March 2019, 16:00: Patrick Dunne (Imperial)

Latest neutrino oscillation results from the T2K experiment

T2K is a long baseline neutrino experiment situated in Japan. We fire beams of muon neutrinos and antineutrinos 295km across the country then observe them using the 50 kTon Super Kamiokande detector. By studying how many of these neutrinos have oscillated into different flavours and whether the oscillations occur differently for antineutrinos we have sensitivity to CP violation in the neutrino sector, the neutrino mass hierarchy and the mixing angles between the neutrino flavours. I will present the latest results from the T2K collaboration including limits on the CP violating parameter \delta_{CP}.

[slides]

Friday 01 March 2019, 16:00: Louie Corpe (UCL)

Hacking the ATLAS detector: looking for exotic long-lived particles using displaced jets

Long-lived particles (LLPs) are nothing new: semi-stable particles abound in the SM. There’s no reason why they wouldn’t occur in extensions to the SM too. The lifetime of exotic LLPs in BSM models is typically unconstrained, and since collider detectors are usually designed assuming that the action happens near the beam crossing, LLPs that decay far from the beamline could easily have been missed by standard searches. To look for them, we therefore need to ‘hack’ our detectors to do something they were not designed to do: search for decays deeper in the detector volume. This talk describes one such search for pairs of neutral, long-lived particles decaying in the ATLAS calorimeter, leading to the formation of narrow, trackless displaced jets.

[slides]

Friday 22 February 2019, 16:00: Fredrik Bjorkeroth (Frascati)

Flavourful axion phenomenology (and impact on Mu3e/Mu2e)

Traditional axion (or ALP) models assume the axion does not distinguish between fermion generations, i.e. it is flavour-universal. This is not the case in flavoured axion models, where the symmetry that dictates fermion mass structures is (or generates) a Peccei-Quinn symmetry. Such models predict flavour-violating axion-fermion couplings which, in highly constrained flavour models, can be fixed by mass and mixing data. I will discuss the phenomenology of flavoured axions, in particular contributions to heavy meson decays and lepton flavour violating processes.

[slides]

Friday 15 February 2019, 16:00: Agni Bethani (Manchester)

Double Higgs production in ATLAS

In the post-Higgs discovery era, studying the Higgs properties and understanding the Higgs mechanism is crucial. The next major milestone in understanding the Higgs mechanism is measuring the tirlinear self-coupling (λΗΗΗ) via Higgs boson pair- production (HH). This would be, arguably, the most important result at the LHC since the Higgs discovery. The HH cross-section is predicted to be very small in the Standard Model (SM) however it can be enhanced in case new physics is present. In the seminar I will discuss the current status of HH searches in ATLAS along with some estimations of what we can achieve in the future.

[slides]

Friday 08 February 2019, 16:00: Nicola McConkey (Manchester)

SBND - a state of the art Liquid Argon TPC for Neutrino Physics

The field of neutrino physics is now moving towards the era of precision physics in order to test the 3-neutrino paradigm, neutrino mass hierarchy and CP asymmetry in the lepton sector. The next generation of neutrino detectors, currently under development and construction, will have sensitivity to the fundamental parameters which describe these phenomena. Liquid argon is an excellent detector medium, with good scintillation and charge transport properties. Coupled with the three dimensional position reconstruction possible with a time projection chamber, it makes for a powerful particle detector which has become one of the detectors of choice for rare event physics, especially in neutrino detection. This rapidly developing field has many technical challenges as the desired detector volume increases to the multi-kiloton scale. I will discuss the Short Baseline Neutrino (SBN) programme, with a focus on the detector technology used, current status and future prospects for the Short Baseline Near Detector (SBND).

Friday 01 February 2019, 16:00: Celeste Carruth (Berkley)

Testing CPT Symmetry with Antihydrogen at ALPHA

One of the biggest unsolved questions in physics is the absence of any large amount of antimatter in the universe. Charge-Parity-Time Symmetry requires that energy convert to equal quantities of matter and antimatter, so at the creation of the universe, the large amount of energy present should have produced equal amounts of matter and antimatter. If an antimatter galaxy existed in the observable universe, we would expect to see radiation coming from particles annihilating in the interstellar space between the matter and antimatter galaxy, but no such signature has yet been discovered. The ALPHA collaboration at CERN combines cold plasmas of antiprotons and positrons to make and trap antihydrogen, and then performs precision measurements on the trapped antimatter. I'll discuss our method for trapping antihydrogen and our recent results of the hyperfine transition and the 1S-2S and 1S-2P spectroscopies.

[slides]

Friday 25 January 2019, 16:00: NO SEMINAR

Friday 18 January 2019, 16:00: Tessa Baker (QMUL)

The Gravitational Landscape for the LSST Era

The Large Synoptic Survey Telescope (LSST), due for first light later this year, spearheads the next generation of cutting-edge astronomical survey facilities. One of its key science goals is to settle questions surrounding dark energy or possible corrections to General Relativity, which are posited to resolve outstanding problems of the standard cosmological model. In this talk I’ll explain how we plan to use LSST to test of the landscape of extended gravity theories. In particular, I’ll focus on the new wave of parameterised techniques developed as the smartest way to probe the landscape of gravity/dark energy models in the current literature. I’ll also discuss some exciting theoretical developments, sparked by recent gravitational wave detections, that offer powerful insights on this model space.

Friday 11 January 2019, 16:00: Jennifer Ngadiuba (CERN)

Deep Learning on FPGAs for L1 trigger and data acquisition for particle physics

Machine learning methods are becoming ubiquitous across particle physics. However, the exploration of such techniques in low-latency environments like Level-1 (L1) trigger systems has only just begun. In this talk, I will present a new software, based on High Level Synthesis, to generically port several kinds of network models (BDTs, DNNs, CNNs) into FPGA firmware. The task of tagging high-pT jets as H->bb candidates using jet substructure is considered here as benchmark physics use case. The resource usage and latency are mapped out versus types of machine learning algorithms and their hyper-parameters. A set of general practices to efficiently design low-latency machine-learning algorithms on FPGAs will be discussed.

[slides]

Friday 14 December 2018, 16:00: Alexander Deisting (RHUL)

Taking a Time Projection Chamber to high pressure

Time Projection Chambers (TPCs) have been employed with great success as tracking detectors and to provide particle ID, since they provide a large active volume and low momentum threshold for particle detection. We currently develop a high pressure TPC (HPTPC) which can operate at gas pressures of up to 5 barA. Increasing the pressure allows to increase the target mass inside the active volume, thus making a HPTPC a promising candidates to characterise neutrino beams at the next generation long baseline neutrino oscillation experiments such as DUNE or Hyper-K. Our HPTPC prototype features a gas amplification stage with three parallel meshes, charge readout at each mesh and an optical readout with four CCD cameras. The talk will focus on the hardware of the detector, its operation and the according challenges as well as some measured results. Possible future developments will be discussed as well.

[slides]

Friday 07 December 2018, 16:00: Loredana Gastaldo (Heidelberg)

Metallic Magnetic Calorimeters for Neutrino Physics

The wish to understand properties of neutrinos has been driving very challenging experiments since the discovery of these elusive particles. In the early ’80, the development of low temperature detectors, operated at millikelvin temperatures, was strongly motivated by the possibility to enhance our knowledge on neutrino Physics. Even today, in the landscape of experiments investigating neutrino properties, low temperature detectors are still playing a very important role. This talk will describe the use of a particular type of low temperature detectors, metallic magnetic micro-calorimeters in experiments for the determination of the electron neutrino mass and for the search of neutrinoless double beta decay. Finally we will discuss other applications as search for keV sterile neutrinos or measurements of coherent neutrino nucleus scattering in which metallic magnetic micro-calorimeters could play a very important role.

[slides]

Friday 30 November 2018, 16:00: Chris Stoughton (Fermilab)

Muon g-2 and other news

After 50 years of operation, Fermilab is still going strong. I will discuss the motivation, status, and prospects of the FNAL g-2 experiment. I'll place it in historical context, especially regarding Fermilab's future programs. I will end with a brief explanation of Fermilab's "smallest" experiment, the Holometer, which measures effect of Planck-scale physics.

[slides]

Friday 16 November 2018, 16:00: Andi Chisholm (Birmingham)

Searching for Higgs boson decays to charm quark pairs with charm jet tagging at ATLAS

The Standard Model (SM) Higgs boson is expected to decay to a charm quark pair in around 3% of cases. While this number seems small, the success of the LHC Higgs boson measurement programme is such that this contribution represents one of the largest expected contributions to the total Higgs boson decay width for which we have no experimental evidence. Furthermore, all experimental evidence for Yukawa couplings is limited to the third generation fermions and the smallness of the SM charm quark Yukawa coupling makes it particularly sensitive to modifications from potential physics beyond the SM. I will describe a novel charm jet tagging algorithm recently commissioned by the ATLAS experiment and discuss how it can be employed to perform the first direct search for Higgs boson decays to charm quark pairs with the ATLAS experiment (Phys. Rev. Lett. 120 (2018) 211802, arXiv:1802.04329). Looking beyond this LHC Run 2 result, the prospects and projected sensitivity for this channel at the HL-LHC will also be discussed.

[slides]

Friday 09 November 2018, 16:00: Jeanne Wilson (QMUL)

SNO+: Current Status and Prospects

The SNO+ experiment is a multi-purpose low energy neutrino experiment based in the SNOLAB deep underground facility in Canada. The experiment builds on the infrastructure of the successful SNO experiment, with liquid scintillator replacing the original heavy water detection medium. The main goal of SNO+ is to search for neutrino-less double beta decay of tellurium-130, which will be dissolved in the liquid scintillator. If observed, neutrino-less double beta decay would confirm the Majorana nature of neutrinos and provide information on absolute neutrino mass. Additionally, SNO+ plans to make measurements of reactor neutrinos, geo-neutrinos, solar neutrinos and will be sensitive to neutrinos from galactic supernovae. For the past year, SNO+ detector commissioning has involved collecting data with H2O as a detection medium, allowing observation of solar neutrinos with extremely low background and a search for invisible modes of nucleon decay, which will be presented in this talk.

[slides]

Friday 02 November 2018, 16:00: Ioana Maris (ULB)

Current status and future of Ultra High Energy Cosmic Rays experiments

The Earth's atmosphere is constantly bombarded by ultra high energy cosmic rays (UHECRs). These particles carry the largest energies known to us: they can reach more than 10²⁰ eV. Their flux is very low, and thus very large detectors were built to be able to detect the secondary particles produced by UHECRs after entering the atmosphere. I will present the results of the forerunner experiments, Pierre Auger Observatory and Telescope Array, regarding the energy spectrum, mass composition and arrival directions. Even though a large progress has been made in the last 10 years, we still do not know where these particles are coming from. In the last part of this talk I will present the future plans to advance in the quest of the origin of UHECRs.

[slides]

Friday 26 October 2018, 16:00: Eram Rizvi (QMUL)

Precision EW Measurements from ATLAS - sin^2\theta_eff

The phenomenal operation of the LHC in Run-1 has allowed high precision measurements to be attained for single vector boson production in pp collisions. A new measurement of the cross section for Z\gamma production at \sqrt{s}=8 TeV will be presented triple differentially in dilepton invariant mass, |y| and \cos\theta covering the region 46$<$m$<$200 GeV; 0$<|y|<$3.6; and -1$<$cos\theta$<$+1. The measurement is designed to be simultaneously sensitive to the proton PDFs and to the weak mixing angle. A precision of better than 0.5% in the region m ~ mZ (excluding luminosity uncertainty) is achieved. The value of sin^2\theta_eff is extracted using this cross section data, and also using the approach of scattering amplitude coefficients. An accuracy of ±36 x 10^{-5} is achieved reaching the combined CDF+D0 accuracy and approaching the LEP and SLD results.

[slides]

Friday 19 October 2018, 16:00: Physics Gala

No seminar this week

TBC

Friday 12 October 2018, 16:00: Christoph Andreas Ternes (IFIC Valencia)

Status of 3-neutrino oscillations

In this talk I will present the current status of neutrino mixing angles and masses. I will explain how simulations are performed and give a brief introduction to the theory of neutrino oscillations. Afterwards I will discuss all the experiments included in the global fit, before going to the results of the combined analysis. There I will focus on the currently open problems, such as atmospheric octant, CP-violation and neutrino mass ordering.

Thursday 14 June 2018, 16:00: Teppei Katori (QMUL)

Observation of a Significant Excess of Electron-Like Events in the MiniBooNE Short-Baseline Neutrino Experiment

The MiniBooNE experiment at Fermilab reports results from an analysis of electron neutrino (nue) appearance data from 1.3E21 protons on target (POT) in neutrino mode, an increase of approximately a factor of two over previously reported results (PRL110(2013)161801). A nue charged-current quasi-elastic (CCQE) event excess of 381.2 +/- 85.2 events (4.5sigma) is observed in the energy range 200 < EnuQE < 1250 MeV. Combining these data with the electron anti-neutrino (nuebar) appearance data from 1.1E21 POT in antineutrino mode, a total nue plus nuebar CCQE event excess of 460.5 +/- 95.8 events (4.8 sigma) is observed. If interpreted in a standard two-neutrino oscillation model (numu to nue), the best oscillation fit to the excess has a probability of 20.1% while the background-only fit has a chi2-probability of 5E-7 relative to the best fit. The MiniBooNE data are consistent in energy and magnitude with the excess of events reported by the Liquid Scintillator Neutrino Detector (LSND), and the signicance of the combined LSND and MiniBooNE excesses is 6.1 sigma. All of the major backgrounds are constrained by in-situ event measurements, so non-oscillation explanations would need to invoke new anomalous background processes. Although the data are fit with a standard oscillation model, other models may provide better fits to the data. https://arxiv.org/abs/1805.12028

[slides]

Friday 01 June 2018, 16:00: Justin Evans (Manchester)

A combined view of sterile-neutrino constraints from CMB and neutrino-oscillation measurements.

I will present a comparative analysis of constraints on sterile neutrinos from the Planck experiment and from current and future neutrino-oscilllation experiments, as reported in S. Bridle et al., Phys. Lett. B764, 322 (2017). In this paper, we, for the first time, expressed joint constraints on N_eff and m_eff^sterile from the CMB in the Δm^2, sin^2(2θ) parameter space used by oscillation experiments, and expressed constraints from oscillation experiments in the N_eff, m_eff^sterile cosmology parameter space. We focused on oscillation experiments that probed mixing of the muon flavour into a fourth mass state: MINOS, IceCube, and the SBN programme. I will then present new work in which we have looked at mixing of the electron flavour to allow comparison of CMB constraints with limits from the reactor experiments NEOS and Daya Bay. Finally, we allow both the electron and muon flavours to simultaneously mix with a fourth mass state, and compare CMB constraints to the numubar->nuebar appearance signals from LSND and MiniBooNE.

[slides]

Friday 18 May 2018, 16:00: Anne Norrick (William&Mary)

Recent and upcoming Results from the MINERvA Experiment

The MINERvA experiment is a dedicated neutrino cross section experiment stationed in the Neutrinos from the Main Injector (NuMI) beam line at Fermi National Accelerator Laboratory in Batavia, IL, USA. Recent results from the MINERvA experiment, as well as upcoming results using a beam of increased energy and intensity and their impact on the field will be discussed.

Friday 11 May 2018, 16:00: Jim Dobson (UCL)

Searching for dark matter with the LUX and LUX-ZEPLIN direct detection experiments

For the past decade liquid xenon time-projection chambers (TPCs) hidden deep underground have led the race to make a first direct detection of dark matter here on Earth. In this talk I’ll present the final results from the recently completed Large Underground Xenon (LUX) experiment as well as the status and physics reach of its successor, the 40 times as massive LUX-ZEPLIN experiment currently being constructed and due to start data taking in 2020.

Friday 04 May 2018, 16:00: Giuliana Galati (Naples)

Final results of the OPERA experiment on tau neutrino appearance in the CNGS beam

The OPERA experiment (Oscillation Project with Emulsion tRacking Apparatus) was designed to conclusively prove the muon neutrino into tau neutrino oscillation in appearance mode. In this talk the improved and final analysis of the full data sample, collected between 2008 and 2012, will be shown. The new analysis is based on a multivariate approach for event identification, fully exploiting the expected features of tau neutrino events, rather than on the sheer selection of candidate events by independent cuts on topological or kinematical parameters as in previous analyses. It is performed on candidate events preselected with looser cuts than those applied in the previous cut-based approach. Looser cuts increase the number of tau neutrino candidates, thus leading to a measurement of the oscillation parameters and of the tau neutrino properties with a reduced statistical uncertainty. For the first time ever, Delta m^2_{23} has been measured in appearance mode, tau neutrino CC cross-section has been measured with a negligible contamination from τ antineutrinos and tau neutrino lepton number has been observed. Moreover, given the higher discrimination power of the multivariate analysis, the significance of the tau neutrino appearance is increased.

[slides]

Friday 27 April 2018, 16:00: Michela Massimi (Edinburgh)

Perspectival modeling at LHC

The goal of this paper is to address the philosophical problem of inconsistent models, and the challenge it poses for realism and perspectivism in philosophy of science. I analyse the argument, draw attention to some hidden premises behind it, and deflate them. Then I introduce the notion of “perspectival models” as a distinctive class of modeling practices, whose primary function is heuristic or exploratory. I illustrate perspectival modeling with two examples taken from contemporary high-energy physics at LHC, CERN (one from ATLAS concerning pMSSM-19 and one from the CMS experiment). These examples are designed to show how a plurality of seemingly incompatible models (once suitably understood) is in fact methodologically very important for scientific progress and for advancing knowledge in cutting-edge areas of scientific inquiry.

Friday 13 April 2018, 16:00: Stephen West (RHUL)

Dark Matter models

I will start by reviewing a range of non-standard dark matter models including models employing asymmetric dark matter and freeze-in. I will then go on to outline models of Nuclear Dark Matter, where the dark matter states are composite objects consisting of ``dark nucleons”. I will outline some of the novel features of this idea and how the composite nature can lead to interesting signatures in direct detection experiments.

Friday 06 April 2018, 16:00: Tuomas Rajala (UCL)

Detecting local scale interactions in highly multivariate point patterns

Highly multivariate point patterns, such as the location patterns of 300 different plant species in a rainforest, are the big data of point pattern statistics. One of the main data analysis goals is the detection of local scale interactions between different point types/species. This talk will discuss two approaches for detecting such interactions: A Monte Carlo framework based on pairwise non-parametric tests, and a multivariate Gibbs model technique relying on automatic variable selection.

Thursday 22 March 2018, 16:00: Tianlu Yuan (UW-Madison)

IceCube: a nu-window into the Universe

The IceCube Neutrino Observatory, a cubic-kilometer in-ice detector at the South Pole, offers a unique window into the smallest and largest scales of our universe. Over the past several years, IceCube has detected the first high-energy neutrinos of astrophysical origin, measured atmospheric neutrino oscillations, and performed searches of neutrino sources throughout the sky. As more data is collected, a reduction of systematic uncertainties becomes ever more important for neutrino astronomy and neutrino property measurements in IceCube. These two paths are connected as, at the highest energies, the angular resolution of events without an observable muon is limited primarily by ice-property uncertainties. To pave the road forward, in this talk I will explore improvements to event reconstruction and systematic treatment in the high-energy starting event (HESE) analysis. I will discuss a new high-energy cross-section measurement using the HESE sample and a novel calculation of the atmospheric neutrino background. I will conclude with an outlook for the future with IceCube-Gen2.

Friday 16 March 2018, 16:00: Seth Zenz (Imperial)

Understanding the Higgs Boson: Where We Are, Where We're Going, and How To Get There

In 2012, the ATLAS and CMS experiments at the CERN Large Hadron Collider discovered a new particle. With analysis of data through 2016 now largely completed, we know more precisely than ever that this particle is highly consistent with the Standard Model (SM) Higgs boson. But is the SM realized exactly, or do some differences in the Higgs boson's properties provide a window into new physics? During the 2020's and 2030's, the High Luminosity LHC will supply a large enough dataset to answer this question with very precise and fine grained measurements. I will outline the current understanding of the Higgs boson, the plans for long-term studies at the LHC, and the measurements we can make now to build up our knowledge in the medium-term and prepare better for the long program ahead.

[slides]

Friday 09 March 2018, 16:00: Kate Pachal (SFU)

Searches for new low-mass resonances in jetty events at ATLAS

"Searches for beyond-standard-model particles in dijet invariant masses have been a been a key feature of physics programs across 30 years of collider experiments. As no new particles at high masses have yet been discovered, some analyses have moved from pushing this final state towards higher and higher scales in favour of searching for small cross section or small branching ratio signals at lower masses. This is ideal for searching for dark matter mediator candidates, where the dijet channel can be a powerful constraint. Low masses pose a serious challenge for searches in fully hadronic final states because of the trigger prescales which make dataset accumulation difficult in this regime. Two ways around this constraint have been explored in Run II: first, the analysis can be performed with minimal event information at the level of the trigger. This poses a lot of unique technical challenges because of the need for a custom jet calibration. Second, the analysis can search for dijet resonances produced in association with an object which can be used for triggering: a higher-pT jet or a photon. This seminar will discuss the most recent public results for both analysis methods."

[slides]

Friday 02 March 2018, 16:00: Kate Pachal (SFU) — POSTPONED!!!

POSTPONED!!! Searches for new low-mass resonances in jetty events at ATLAS

Searches for beyond-standard-model particles in dijet invariant masses have been a been a key feature of physics programs across 30 years of collider experiments. As no new particles at high masses have yet been discovered, some analyses have moved from pushing this final state towards higher and higher scales in favour of searching for small cross section or small branching ratio signals at lower masses. This is ideal for searching for dark matter mediator candidates, where the dijet channel can be a powerful constraint. Low masses pose a serious challenge for searches in fully hadronic final states because of the trigger prescales which make dataset accumulation difficult in this regime. Two ways around this constraint have been explored in Run II: first, the analysis can be performed with minimal event information at the level of the trigger. This poses a lot of unique technical challenges because of the need for a custom jet calibration. Second, the analysis can search for dijet resonances produced in association with an object which can be used for triggering: a higher-pT jet or a photon. This seminar will discuss the most recent public results for both analysis methods.

Friday 23 February 2018, 16:00: Francesco Coradeschi (Cambridge)

Precision physic at colliders: introducing reSolve, a transverse momentum resummation tool

Since the early days of the Large Hadron Collider (LHC), a large part of the experimental effort was focused on direct searches for signals of New Physics. It is however important (and increasingly so, given the absence of any direct detection so far) to also explore alternative strategies, and foremost among these is precision physics. Traditionally, hadron machines such as the LHC were not considered particularly well-suited to precision studies, but experimental collaborations at CERN have already provided us with excellent measurements which exceed our best theoretical predictions precision-wise, and can only be expected to get better as the LHC continues its run. It is crucial for the theoretical community to keep up with this trend, especially considering that most realistic, still viable, extensions of the Standard Model (SM) are compatible with only small deviations from SM predictions, at LHC energies, for arbitrary observables. The transverse momentum spectrum is a particularly interesting observable for the precision program: in general processes, a majority of events is produced at relatively soft transverse momentum scales, and the physical behaviour at these soft scales is an highly nontrival prediction of perturbative QCD (and thus of the SM) which requires a resummation of logarithmically-enhanced contributions to all orders in the strong coupling \alpha_s. In this talk, I will introduce the new tool reSolve, a Monte Carlo differential cross-section and parton-level event generator whose main new feature is to add transverse momentum resummation to a general class of inclusive processes at hadron colliders. reSolve uses the impact parameter formalism, which is particularly well-suited to general studies. During the talk I will briefly review transverse momentum resummation in general, the peculiarities of its implementation in reSolve, and conclude commenting some of the possible phenomenological applications and future developments.

[slides]

Friday 16 February 2018, 16:00: Nassim Bozorgnia (Durham)

The dark halo of Milky Way-like galaxies

One of the major sources of uncertainty in the interpretation of dark matter direct and indirect detection data is due to the unknown astrophysical distribution of dark matter in the halo of our Galaxy. Realistic numerical simulations of galaxy formation including baryons have recently become possible, and provide important information on the properties of the dark matter halo. I will discuss the dark matter density and velocity distribution of Milky Way-like galaxies obtained from high resolution hydrodynamical simulations. To make reliable predictions for direct and indirect detection searches, we identify simulated galaxies which satisfy the Milky Way observational constraints. Using the dark matter distribution extracted from the selected Milky Way-like galaxies, I will present an analysis of current direct detection data, and discuss the implications for the dark matter interpretation of the Fermi GeV excess.

[slides]

Friday 09 February 2018, 16:00: Stefan Guindon (CERN)

Recent ATLAS Results in the search for ttH production

The observation of the production of ttH is an important test of the top Yukawa coupling of the Higgs boson, and one of the main goals of Run-2 of the Large Hadron Collider. It remains one of the most important characteristics of the Higgs boson which has yet to be directly observed. Many models of new physics beyond the Standard Model predict significant deviations of this coupling, which would be directly observable via the measurement of ttH production. The new ATLAS searches for ttH associated production at centre-of-mass energies of 13 TeV will be presented. The search targets several Higgs boson decays, including final states with multiple b-quarks, multileptons, and two photons.

Friday 02 February 2018, 16:00: Yiannis Andreopoulos (UCL)

Deep Learning from Compressed Spatio-Temporal Representations of Data

Deep learning has allowed for (and incentivised) researchers to look at data volumes and processing tasks that have previously only been hypothesized. While the first-generation of deep supervised learning achieved significant advances over shallow learning methods, it is increasingly becoming obvious that many approaches were naive in their design and we are only scratching the surface of what is possible. The notion of strong supervision (i.e., the use of labels during training) is impractical and easy to fool by adversarial examples and, perhaps most importantly, operating with uncompressed samples (e.g., input image pixels of video or audio) does not scale. For instance, data generated from visual sensing in Internet-of-Things (IoT) application contexts will occupy more than 82% of all IP traffic by 2021, with one million minutes of video crossing the network every second [Cisco VNI Report, Jun. 2017]. This fact, in conjunction with the rapidly-increasing video resolutions and video format inflation (from standard to super-high definition, 3D, multiview, etc.), makes the scale-up of deep learning towards big video datasets unsustainable. To address this issue, we propose to go beyond the pixel representations and design advanced deep learning architectures for classification and retrieval systems that directly ingest compressed spatio-temporal activity bitstreams produced by: (i) mainstream video coders and (ii) neuromorphic vision sensing cameras. By exploiting the compressed nature of our inputs, our approach can deliver 100-fold increase in processing speed with comparable classification or retrieval accuracy to state-of-the-art pixel-domain systems and has the potential to be extended to self-supervised deep learning. The talk will explain the key steps of our approach and can motivate researchers to think carefully about the sensing and supervision modalities of their problems prior to embarking on the use of deep learning tools for data analysis. Related paper: https://arxiv.org/abs/1710.05112

Friday 26 January 2018, 16:00: Jonathan Davis (Kings)

CNO Neutrino Grand Prix: The race to solve the solar metallicity problem

Several next-generation experiments aim to make the first measurement of the neutrino flux from the Carbon-Nitrogen-Oxygen (CNO) solar fusion cycle. This will provide crucial new information for models of the Sun, which currently are not able to consistently explain both helioseismology data and the abundance of metal elements, such as carbon, in the solar photosphere. The solution to this solar metallicity problem may involve new models of solar diffusion or even the capture of light dark matter by the Sun. I look at how soon electronic-recoil experiments such as SNO+, Borexino and Argo will measure the CNO neutrino flux, and the challenges this involves. I also consider experiments looking for nuclear-recoils from CNO neutrinos, which requires sensitivity to very low energies, and discuss how the same technology is also key to direct searches for sub-GeV mass dark matter.

[slides]

Friday 19 January 2018, 16:00: Chris Backhouse (UCL)

New results from NOvA

The phenomenon of neutrino oscillations, which implies that neutrinos are not massless as we had previously believed, raises a wealth of new and intriguing questions. What is the ordering of the neutrino mass states? Might neutrino oscillations violate matter/antimatter symmetry? What structure, if any, does the neutrino mixing matrix have? The NOvA experiment directly addresses these questions by measuring the changes undergone by a powerful neutrino beam over an 810 km baseline, from its source at Fermilab, Illinois to a huge 14 kton detector in Ash River, Minnesota. I will give a brief overview of neutrino oscillations, then present updated NOvA measurements of the disappearance of muon neutrinos and their transformation into electron neutrinos, the implications of these results, and prospects for the future.

[slides]

Friday 15 December 2017, 16:00: Silvia Pascoli (Durham)

Going beyond the standard 3-neutrino mixing scenario

Although the standard 3 neutrino mixing scenario fits very well most existing data, the possibility that new effects, e.g. sterile neutrinos, NSI…, exist is still open. In this talk I will focus mainly on sterile neutrinos. They are neutral fermions which do not have Standard Model interactions but mix with light neutrinos. They constitute a minimal extension of the standard model. They have interesting signatures in cosmology and in laboratory searches. I will review the current situation, discussing the hints for their existence and their tests in neutrino oscillation, beam dump, SBN, DUNE and other experiments. I will conclude presenting a possible explanation of the MiniBooNE excess which is compatible with current data.

Friday 08 December 2017, 16:00: Mauricio Bustamante (Niels Bohr Institute)

Heaven-sent neutrino interactions from TeV to PeV

Neutrino interactions are vital to particle physics and astrophysics. Yet, so far, they had remained unprobed beyond neutrino energies of 350 GeV. Now, thanks to the discovery of high-energy astrophysical neutrinos by IceCube, we have measured neutrino-nucleon cross sections from a few TeV up to a few PeV. We did this by using the Earth itself as a target: neutrino interactions with matter inside the Earth imprint themselves on the distribution of neutrino arrival directions at the detector. When measuring high-energy particle interactions, the sky is the limit.

[slides]

Friday 01 December 2017, 16:00: Anthony Hartin (UCL)

Strong field QED effects in the quantum vacuum generated by laser-electron interactions

When considered in a non-perturbative QFT, the interactions of intense lasers and relativistic charged particles lead to novel strong field QED effects amenable to experimental tests with available technology. I review the theory and simulation strategy necessary in order to design discovery experiments for these effects. The intense laser field is taken into account exactly in the bound Dirac equation whose solutions are required for different field configurations. The simulation strategy requires a PIC code combined with a monte-carlo of the quantum interactions. The workhorse process for such experiments is the trident process which I will also review.

Friday 24 November 2017, 16:00: Mitesh Patel (Imperial)

Anomalous measurements at the LHCb experiment

A number of measurements of B-meson decays made at the LHCb experiment give anomalies with respect to the predictions of the Standard Model. The status of the relevant measurements, the connections between them and their theoretical interpretation will be discussed, along with the prospects for the future.

[slides]

Friday 17 November 2017, 16:00: Pontus Stenetorp (UCL)

DIS CDT seminar: Artificial Intelligence for Reading the Scientific Literature

We are currently experiencing an unprecedented increase of interest in applying Artificial Intelligence methods for various tasks. Spurred on advances using modern reincarnations of neural networks – Deep Learning – machine learning-based approaches have seen recent successes in complex games like Go, autonomous vehicles, and language-based question answering. In this talk I will present the current state of the art in Natural Language Processing (NLP) and its limitations. I will then relate this to previous and ongoing efforts in applying NLP-methods to the scientific literature – allowing scientists to cope with an ever increasing number of publications. Primarily I will cover ongoing work from the UCL Machine Reading group on text-based multi-step inference applied to the biomedical literature and a collaboration with the UCL Space & Climate Physics to track astronomical measurements in the astrophysics literature.

[Video]

Friday 10 November 2017, 16:00: John LoSecco (Notre Dame)

The History of the Atmospheric Neutrino Anomaly

This talk covers the early days of particle astrophysics when it was slowly realized that the major background to proton decay, atmospheric neutrino interactions, were an important discovery in their own right.

[slides]

Friday 03 November 2017, 16:00: Moritz Backes

Recent results from Supersymmetry Searches at ATLAS

This talk discusses a selection of the latest ATLAS results for searches for supersymmetric (SUSY) particles performed with pp collisions at a centre-of-mass energy of 13 TeV, using the full 2015 and 2016 dataset. Weak and strong production of SUSY particles in both R-Parity conserving and violating scenarios are considered assuming either prompt decays or longer-lived states.

[slides]

Friday 27 October 2017, 16:00: Jens Dopke (RAL)

Reading charcoal: Using HEP detectors to decipher papirii

I will introduce the problem of reading ancient documents, in this particular project working on reconstruction of text from scrolls found in Herculanuem near Mt. Vesuvis. These are made from papyrus and have been written on using organic inks. After the eruption of Mt. Vesuvius in 79 AD, these been slow-cooked under exclusion of oxygen, and hence turned into lumps of charcoal. All attempts of unrolling these subjects have been destructive. First indications show that dark-field x-ray imaging allows to make the ink of these documents visible and there is good hope that this assumption holds for multi-layered documents that cannot be unrolled. I will introduce dark-field x-ray imaging, report on where we are with the project, what’s lacking at the moment and where we plan to get to within the next year(s).

Friday 20 October 2017, 15:00: Valerio Dao: NOTE: unusual time and location: Harrie Massey

Physics with Hbb at ATLAS

Since its discovery in 2012 the Higgs boson particle has opened new possibilities to further improve our understanding of the Standard Model physics landscape. Precise characterisation of its production and its properties could be used to indirectly probe for new physics effects and, at the same time, the decay of new particles could directly lead to signatures with a SM-like Higgs boson in the final state. The decay of the Higgs boson into a b-quark pair has, in this respect, a key role; while experimentally very challenging, the large branching ratio makes it the largest contributor to the total width of the Higgs boson and, thanks to the large rate, provides the best chance to see evidence for new phenomena that lead to deviations at high pT. Recently the ATLAS collaboration achieved an important milestone by obtaining the evidence for the H->bb decay in the associated production of the Higgs boson and a vector boson using Run2 data at 13 TeV. This seminar will mainly focus on this recent result discussing the experimental challenges that have been faced to extract the signal from a very large background. In addition, key examples of how H->bb signature could be used for directly searching for new physics effects will be given.

Friday 01 September 2017, 16:00: Evan Niner (Fermilab)

Deep Learning Applications of the NOvA Experiment

The NOvA experiment is a long-baseline neutrino oscillation experiment that uses two detectors separated by 809 kilometers to measure muon neutrino disappearance and electron neutrino appearance in the beam produced at Fermilab. These oscillation channels are sensitive to unknown parameters in neutrino oscillations including the mass hierarchy, θ23, and CP violation. In this talk I will focus on the development and application of deep learning algorithms to the task of event reconstruction and classification in NOvA. These algorithms, adapted from computer vision applications, resulted in a performance gain equivalent to a 30% increase in exposure in the 2016 analysis. I will also look at future deep learning applications.

[slides]

Wednesday 12 July 2017, 16:00: Steven Prohira (Kansas University)

Radio interactions with particle-shower plasmas, with implications for high-energy astro-particle physics

The collision of a high-energy particle with stationary matter, such as ice, results in a shower of secondary particles. As these secondary particles traverse the interaction medium, cold ionization electrons are produced. For high enough primary particle energies, this cloud of ionization electrons is dense enough to form a tenuous plasma which may reflect radio-frequency (RF) energy. As such, RF scatter techniques have been proposed as a robust technology to remotely detect such high-energy particle interactions by illuminating a detection volume with RF energy and remotely monitoring the same volume for a reflected RF signal from a particle-shower plasma. Though the Telescope Array RADAR (TARA) experiment, the first dedicated attempt at the radio-scatter method, yielded no results, the intriguing lack of signal has caused renewed interest in the technique. Surprisingly, a dedicated laboratory measurement of RF scatter from particle-showers has never been performed at high (GeV) energies. This talk will discuss experimental results from TARA and will detail a laboratory measurement to take place at the End-Station facilities at SLAC to quantify the parameters of the particle-shower plasma. A high-energy electron beam will be fired into a large target to initiate a shower from which RF will be reflected. The observables from this measurement will be discussed, along with outlook.

[slides]

Friday 23 June 2017, 16:00: Prof. Tsutomu Yanagida (IPMU, U. of Tokyo)

The Origin of Matter in the Universe

Paul Dirac proposed the baryon symmetric universe in 1933. This proposal has become very attractive now since it seems that all pre -existing asymmetry would have been diluted if we had an inflationary stage in the early universe. However, if our universe began baryon symmetric, the tiny imbalance in numbers of baryons and anti-baryons which leads to our existence, must have been generated by some physical processes in the early universe. In my talk I will show why the small neutrino mass is a key for solving this long standing problem in understanding the universe we observe today.

[slides]

Friday 16 June 2017, 16:00: Sarah Bridle (Manchester)

Gastrophysics: Food security for astro/physicists

In this seminar I will describe my motivations for being interested in food research, and my belief that STFC researchers bring a lot of relevant skills to the challenges of providing food that consumers want. The STFC Food Network+ aims to bring STFC researchers and facilities together with food researchers and industry, through network meetings and funding for new projects. Some background about food: There is an impending perfect storm of pressure on our food production system, with increasing population and changing consumer tastes, in the face of rising temperatures and extreme weather events. Tim Gore, head of food policy and climate change for Oxfam, said “The main way that most people will experience climate change is through the impact on food: the food they eat, the price they pay for it, and the availability and choice that they have.”. Yet, at the same time, food production is a bigger contributor to climate change than transport. A 2014 Chatham House report states “Dietary change is essential if global warming is not to exceed 2C.”.

[slides]

Friday 02 June 2017, 16:00: Edward Daw (Sheffield)

Axions and Axion-Like Particles

In recent years, searches for new physics beyond the standard model have focussed on the electroweak scale, using channels that are reachable in high energy accelerators and through induced interactions of hypothesised electroweak-scale relic particles (WIMPs) in tonne-scale direct search experiments. A second possibility which is scientifically just as well-motivated is that the dark matter consists of much lighter pseudoscalars, called axions, whose origin is in low energy quantum chromodynamics, whose coupling to ordinary matter is feeble because their low mass, and consequently their feeble couplings to other particles, renders them 'invisible' to ordinary accelerator searches. The same feeble couplings mean that axions have very long decay times, so that relic axions generated in the very early Universe may be the dark matter evidenced through its gravitational effects today. I shall survey the field of axion-sector experimental searches. Experiments that look directly for the axion itself attempt to induce dark matter axions to convert into microwave photons in closed electromagnetic resonators. Other experiments identify other by-products of the symmetry breaking mechanism that may have yielded axions; these other by-products are sometimes called ALPs (axion-like particles), and experiments to search for ALPs typically use a 'light shining through a wall' technique. Overall this is an exciting and growing field. I will also discuss some of my own work on axion searches with the ADMX experiment, aimed towards improvements in the sensitivity and search rate of such experiments by means of novel modifications to the resonant detector design.

Friday 26 May 2017, 16:00: Leigh Whitehead (CERN)

Sterile Neutrino searches with MINOS and MINOS+

Three-flavour neutrino oscillations have proved very successful in describing the observed neutrino oscillation data. However, there are also some anomalies, including the excesses of appeared electron neutrino interactions in LSND and MiniBooNE, and a sterile neutrino state at a larger mass-splitting scale can provide an explanation for these results. The MINOS/MINOS+ experiment was a long-baseline neutrino experiment in the US, collecting beam and atmospheric neutrino interactions from 2003 until 2016. MINOS was optimised for the study of muon neutrino disappearance in the NuMI beam at Fermilab. The continuation of the experiment with a medium energy beam configuration is called MINOS+. A sterile neutrino in MINOS/MINOS+ would appear as a modulation on the three-flavour oscillations. A search for sterile neutrinos has been performed using charged-current and neutral-current interactions in two detectors separated by a distance of 734km. The inclusion of two years of MINOS+ data and an improved fit method provides a much increased sensitivity over the previous MINOS result that was combined with Daya Bay.

[slides]

Friday 19 May 2017, 16:00: Gabriel Facini (UCL)

Searches for new phenomena with the ATLAS detector

Many theories beyond the Standard Model (BSM) predict new phenomena accessible by the LHC which prevent the need of fine-tuning of the Higgs Boson mass or expand the gauge sectors of the SM or the nature of Dark Matter for example. Searches for new physics models are performed using the ATLAS experiment at the LHC focusing on exotic signatures that can be realized in serval BSM theories. The results reported use the pp collision data sample collected in 2015 and 2016 by the ATLAS detector at the LHC with a centre-of-mass energy of 13 TeV.

Friday 05 May 2017, 16:00: Christopher McCabe (GRAPPA)

Low energy signals in xenon detectors: from supernova neutrinos to light dark matter

One of the major achievements of the LUX collaboration was to accurately calibrate xenon dark matter direct detection experiments to sub-keV energies. This means that reliable predictions of low-energy signals can now be performed. In this talk, I’ll explore new low-energy signals from neutrinos and low-mass dark matter that could be measured with the forthcoming generation of multi-tonne xenon detectors. Based primarily on arXiv:1606.09243 and arXiv:1702.04730.

[slides]

Friday 05 May 2017, 16:00: Leigh Whitehead (CERN)

MINOS TBC

Friday 28 April 2017, 16:00: Tommi Tenkanen (QMUL)

Observational properties of feebly interacting dark matter

Can dark matter properties be constrained if dark matter particles interact only feebly with the Standard Model fields? The answer is yes. By studying both cosmological and astrophysical constraints, we show that stringent constraints on dark matter properties can be derived even in case the dark matter sector is practically uncoupled from the Standard Model sector. By taking the Higgs portal model as a representative example, we study in detail scenarios where the hidden sector does not thermalize with the Standard Model sector and, among other things, derive a lower bound on dark matter self-interaction strength.

[slides]

Friday 21 April 2017, 16:00: Jonas Lindert (IPPP Durham)

High-precision predictions for V+jet production

In LHC searches for Dark Matter one of the dominant systematic uncertainties arises from the determination of the irreducible Z(->vv)+jet background. The modelling of this background relies on accurate measurements of V+jet production processes with visible final states and their extrapolation to the signal region via a global fit based on high-precision Standard Model predictions for pp->W+jets, pp->Z+jets and pp->gamma+jets including higher-order QCD and EW corrections. I will present such predictions with a focus on the mandatory determination of robust estimates of remaining theoretical uncertanties at the percent level and their correlation amongst processes.

[slides]

Friday 07 April 2017, 16:00: Luise Skinnari(Cornell)

Track-triggering at CMS for the High-Luminosity LHC

The high luminosity upgrade of the LHC, scheduled for 2024-2025, will increase the luminosity by a factor of 10 beyond the original LHC design. The resulting large datasets will allow precise measurements of Higgs properties, searches for rare processes, and much more. To cope with the challenging environment from the high luminosity, significant upgrades will be required for the LHC experiments. A key upgrade of the CMS detector is to incorporate tracking information in the hardware-based trigger. We are exploring different strategies for performing the hardware-based track finding, including a fully FPGA-based approach. I will give an overview of the CMS track trigger upgrade, describe its expected performance, and show results from developments of a hardware demonstrator system.

[slides]

Friday 31 March 2017, 16:00: Andreas Warburton (McGill/[UCL])

Searches for New Physics on the Intensity Frontier: The Belle II Experiment

The Belle II collaboration comprises over 600 physicists from 23 countries building a detector on the high-luminosity SuperKEKB electron-positron collider in Japan. The detector, a successor to the successful BaBar and Belle experiments, has capabilities complementary to efforts with similar goals at the LHC and is the latest experimental tool in the now three-decade-long B-factory era. I will outline the prospects for discoveries of new physics at Belle II and discuss the latest status and schedule of the accelerator and detector upgrades, currently in progress.

[slides]

Friday 24 March 2017, 16:00: Jose No (KCL)

Beyond simplified models for dark matter searches @LHC: Making a case for the pseudoscalar portal

The Higgs sector is a well-motivated portal to dark matter (DM). I discuss scalar/pseudoscalar portal models for DM, as a powerful tool to exploit the complementarity between LHC searches and direct/indirect DM detection experiments, and their connection to Higgs physics. I then analyze the shortcomings of so-called "simplified DM models" in this context, highlighting the key physics these models fail to capture and its impact on LHC searches.

[slides]

Friday 10 March 2017, 16:00: Mark Lancaster (UCL)

The Fermilab Mu2e Experiment

In the SM the only mechanism to violate charged lepton flavour conservation is via neutrino oscillations which results in a branching rate for neutrinoless muon interactions of order 10^-50. As such any observation of a neutrinoless muon interaction would be evidence of new physics. In this talk I will describe the Fermilab Mu2e experiment that is seeking to detect the neutrinoless conversion of a muon to an electron in the field of a nucleus using 10^20 muons with a branching ratio sensitivity down to 6x10^-17: a factor of 10^4 better than the previous limit which allows the experiment to probe new physics mass scales up to 8000 TeV, well beyond that probed by direct searches at the LHC.

[slides]

Friday 03 March 2017, 16:00: Fady Bishara (Oxford)

The next frontier for Higgs couplings

The LHC experiments have, so far, measured many of the Higgs couplings and found excellent agreement with the minimally-realized electroweak symmetry breaking (EWSB) mechanism in the Standard Model. Nevertheless, there are important couplings that are currently out of reach which test the nature of EWSB and fermion mass generation. This talk will focus on two of them: the charm Yukawa and the hhVV couplings. A measurement of the first would confirm that the 125 GeV Higgs which gives mass to third generation fermions also gives mass the second generation. To this end, I will describe recent ideas to probe the charm Yukawa coupling in particular by using Higgs differential distributions. In the second case, deviations of the hhVV coupling from the SM would signal non-linearity and herald new physics at higher energies. As I will show, double Higgs production in VBF at the LHC can provide such a test at the 20% level by the end of the high luminosity run while a percent level constraint can be obtained at a future circular collider.

[slides]

Friday 10 February 2017, 16:00: Mercedes Paniccia (Geneva)

The Alpha Magnetic Spectrometer on the International Space Station: the era of precision cosmic-ray physics

The Alpha Magnetic Spectrometer (AMS) is the most powerful and sensitive cosmic-ray detector ever deployed in space to produce a complete inventory of charged particles and nuclei in cosmic rays near Earth in the energy range from GeV to few TeVs. Its physics goals are the study of cosmic-ray properties, indirect search for Dark Matter and direct search for primordial antimatter. The improvement in accuracy over previous measurements is made possible through its long duration time in space, large acceptance, built in redundant systems and its thorough pre-flight calibration in the CERN test beam. These features enable AMS to analyse the data to an accuracy of ~1%. Since its installation on the International Space Station in May 2011, AMS has collected more than 90 billion cosmic-ray events and has produced precision measurements of electron, positron, proton, antiproton, He and light nuclei fluxes and of their ratios in cosmic rays of energy ranging from GeV to few TeVs. The percent precision of the AMS results challenges the current understanding of the origin and of the acceleration and propagation mechanisms of cosmic rays in the galaxy and thereby requires new theories to be developed by the physics and astrophysics community. In this talk, after a brief introduction to cosmic-ray physics, I will present the latest AMS results based on its first five years of data taking, pointing out their implication for cosmic-ray modelling and for Dark Matter searches.

[slides]

Friday 27 January 2017, 16:00: Jan Kretzschmar (Liverpool)

Precision W and Z cross-sections and the first measurement of the W boson mass at ATLAS

The Large Hadron Collider has produced more W and Z bosons than any other collider before. The large samples of leptonic bosons decays provide a unique opportunity for precision studies of the strong interaction and the electroweak interaction. These studies are facilitated by the high experimental precision achieved in these measurements after a careful detector calibration. New cross-section measurements allow novel insights into the proton structure. Specifically, strong constraints of the poorly known strange-quark distribution are demonstrated in a NNLO QCD analysis. The mass of the W boson is a key parameter in the global electroweak fit to test the overall consistency of the Standard Model. The first complete W-boson mass measurement at the LHC is presented, which requires an extraordinary control over both experimental and theoretical effects.

[slides]

Friday 20 January 2017, 16:00: Jon Butterworth (UCL)

Making measurements and constraining new physics at the LHC

Particle-level differential measurements made in fiducial regions of phase-space at colliders have a high degree of model-independence. These measurements can therefore be compared to BSM physics implemented in Monte Carlo generators in a very generic way, allowing a wider array of final states to be considered than is typically the case. A new method providing general consistency constraints for Beyond-the-Standard-Model (BSM) theories, using measurements at particle colliders, is presented.

[slides]

Monday 09 January 2017, 16:00: Jordan Myslik (LBNL) — NOTE: UNUSUAL DATE/PLACE!!! Physics E7

The MAJORANA DEMONSTRATOR

Abstract: The MAJORANA DEMONSTRATOR is an experiment searching for neutrinoless double-beta decays of germanium-76. This lepton-number-violating process is connected to the nature, absolute scale, and hierarchy of the neutrino masses. The MAJORANA DEMONSTRATOR consists of two modular arrays of natural and 76Ge-enriched germanium detectors totalling 44.1 kg, located on the 4850' level of the Sanford Underground Research Facility in Lead, South Dakota. While seeking to demonstrate backgrounds low enough to justify a tonne-scale experiment and the feasibility of its construction, the MAJORANA DEMONSTRATOR's ultra-low backgrounds and excellent energy resolution also allow it to probe additional physics beyond the Standard Model. This talk will discuss the physics and the design elements of the MAJORANA DEMONSTRATOR, its results to date, and its future prospects, along with the plans for a future 1 tonne germanium-76 neutrinoless double-beta decay experiment.

[slides]

Friday 16 December 2016, 16:00: Eric Jansen (CMCC)

Numerical ocean modelling and the case of MH370

In this seminar I will take you on a small excursion into the world of numerical ocean modelling, and more specifically: data assimilation. The field of ocean data assimilation is concerned with updating ocean forecasts using daily observations of the ocean state in order to produce more accurate forecasts for the next day. Observations are incredibly diverse: buoys and moorings that measure time-series in a specific location, autonomous vehicles that can dive and resurface, coastal radar systems that measure currents, but also satellite measurements of the sea surface. I will discuss how we can assimilate these observations using a Kalman filter technique, applied to an ensemble of ocean model realisations. The second part of the seminar will focus on how we can apply these ocean models to a real-world problem: the disappearance of flight MH370. Malaysia Airlines flight 370 was a commercial flight from Kuala Lumpur to Beijing, which vanished without a trace in March 2014. It is believed to have crashed somewhere off the west-coast of Australia, but despite extensive search operations the main wreckage was never found. Now, more than two years later, parts belonging to the aircraft are found 4000km away on the African coast. How can we use this information to locate the crash site?

[slides]

Wednesday 14 December 2016, 16:00: Prof. Un-Ki Yang (Seoul National Univ.) — UNUSUAL LOCATION: E7

Searches for heavy neutrinos at the LHC

Heavy neutrinos occur in various extensions of the Standard Model (SM) and may explain the observed small masses of the SM neutrinos via several possible variants of the seesaw mechanism. We present results on searches for heavy neutrinos at the LHC. Searches are performed in the dilepton+jets channel and the trilepton channel, and results are interpreted in terms of the Left-Right Symmetrical model, Type-I, and the Type-III seesaw mechanism.

[slides]

Friday 02 December 2016, 16:00: Clare Burrage (Nottingham)

Detecting Dark Energy with Atom Interferometry

I will discuss the possibility that the nature of the dark energy driving the observed acceleration of the Universe on giga-parsec scales may be determined first through metre scale laboratory based atom interferometry experiments. I will begin by discussing why our attempts to solve the cosmological constant problem lead to the introduction of new, light degrees of freedom. In order to be compatible with fifth force constraints these fields must have a screening mechanism to hide their effects dynamically. However, this doesn’t mean that they are impossible to detect. I will discuss the constraints that arise from a range of laboratory experiments from precision atomic spectroscopy to collier physics. Finally I will show that atom-interferometry experiments are ideally suited to detect a large class of the screening mechanisms known as chameleon. This will then allow us to either rule out large regions of the chameleon parameter space or to detect the force due to the dark energy field in the laboratory.

[slides]

Friday 25 November 2016, 16:00: Lucian Harland-Lang (UCL))

Photon-photon collisions at the LHC

I will discuss the possibilities for using the LHC as a photon colliding machine. The colour singlet nature of the photon means that it can readily lead to exclusive or semi-exclusive events, with limited or no extra particle production in the final state. I will show how such processes provide a well understood environment in which to test the Standard Model and search for BSM physics. This is particularly relevant at the LHC, where these events may be selected using dedicated 'proton tagging' detectors installed in association with ATLAS and CMS. I will also consider the impact of photon-initiated processes on the more common inclusive production modes at the LHC. Here, the photon must be included in addition to the quarks and gluons as a parton in the proton. I will demonstrate that, despite indications to the contrary from earlier studies, the photon parton density in the proton is in fact quite precisely known, and consider the implications for LHC (and FCC) phenomenology.

[slides]

Friday 18 November 2016, 16:00: James Currie (IPPP Durham)

Jet Production at NNLO

Jet production is one of the most ubiquitous yet important reactions at the LHC. Calculating higher order corrections to this observable allows us to gain sensitivity to phenomenological parameters such as the strong coupling and the gluon PDF as well as providing a rigorous test of QCD over a vast kinematic range. It is well known that calculating higher order corrections is a non-trivial task and requires a powerful method to subvert the various infrared singularities present in the calculation. I will introduce the Antenna Subtraction method as a means of calculating finite cross sections and present some recent results obtained by applying this method to the problem of jet production at NNLO.

[slides]

Friday 11 November 2016, 16:00: Marcel Vos (IFIC Valencia))

Future of top Physics

In this seminar I discuss the potential of planned facilities - lepton and hadron colliders - to bring our understanding of the top quark to the next level. The focus is on measurements of top quark properties and interactions with exquisite sensitivity for signals of the physics that lies behind the Standard Model: the top quark mass measurement, the search for FCNC interactions involving top quarks and those characterizing the top quark couplings to the gluon, EW gauge bosons and the Higgs boson. The precision that new experiments can achieve in these key measurements is compared to the current state-of-the-art and the expectation for the complete LHC programme.

[slides]

Friday 04 November 2016, 16:00: Marco Pappagallo (University of Bari & INFN)

exotic hadronic states in LHCb (Penta/Tetra quarks)

The latest years have seen a resurrection of interest in searches for exotic states. Using the data collected at pp collisions at 7 and 8 TeV by the LHCb experiment, unambiguous new observations of exotic charmonia hadrons produced in B and Lambdab decays are presented. Results of a search for a tetraquark state decaying to Bs pi+- are reported as well

[slides]

Friday 28 October 2016, 15:00: Jeff Foreshaw (Manchester) — NOTE EARLIER TIME AND DIFFERENT LOCATION E7!

“Probabilities and Signalling in Quantum Field Theory”

I will talk about a way to compute transition probabilities that works directly that the level of probabilities and not amplitudes. The formalism guarantees that the initial and final states are always linked by a chain of retarded propagators and it has a nice diagrammatic approach.

[slides]

Wednesday 26 October 2016, 14:00: Blackett Lab LT1, Imperial College London

Gravitational Wave Symposium

A half day physics meeting on gravitational waves. Leading scientists from the Astro and HEP communities will present the recent discovery of gravitational waves and future prospects of this new field in fundamental physics. The talks are aimed at interested researchers at all levels across all of London's universities. See: https://indico.cern.ch/event/563302

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Friday 21 October 2016, 13:00–17:00: 2nd year PhD Students — NOTE different time/place!

2nd year PhD talks!

1pm-5pm in E3/E7

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Friday 14 October 2016, 16:00: Sally Shaw (UCL)

The LUX & LZ Dark Matter Experiments: WIMP Hunting in the Black Hills

Discovery of the nature of dark matter is recognised as one of the greatest contemporary challenges in science, fundamental to our understanding of the universe. Weakly Interacting Massive Particles (WIMPs) that arise naturally in several models of physics beyond the Standard Model are compelling candidates for dark matter. The LUX experiment, operated 1.5 km underground in the Davis Cavern of the SURF laboratory, USA, is the world leader in the direct hunt for WIMPs. I will present the latest LUX results and describe the unique in-situ calibrations that have allowed low energy nuclear recoil measurements in liquid xenon, greatly enhancing our sensitivity to low mass WIMPs. I will also discuss the status of LUX’s multi-tonne successor, LZ, demonstrating how its sensitivity is ideally matched to explore the bulk of the remaining theoretically favoured electroweak phase space towards galactic dark matter discovery.

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Friday 07 October 2016, 16:00: Leszek Roszkowski (Sheffield and NCBJ)

Particle dark matter: what it is and how to determine its properties

After a brief introduction I will comment on some recently discussed WIMP candidates for dark matter. In particular, I will provide arguments that a supersymmetric neutralino with mass around 1 TeV and well defined properties has emerged as an attractive and experimentally testable candidate for dark matter in light of measured Higgs boson properties and ensuing implications for supersymmetry searches at the LHC. On the other hand, for a wide range of WIMPs, and independent of any specific particle physics scenarios, when a dark matter signal is eventually measured in direct or indirect search experiments, or both, it may prove rather challenging to work out ensuing WIMP properties.

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Tuesday 19 July 2016, 16:00: Mark Scott (TRIUMF)

T2K and NuPRISM: An experimental solution to the problems of neutrino interactions in long baseline neutrino experiments

T2K is a long baseline neutrino experiment in Japan that has published world-leading measurements of neutrino oscillations and has the potential to find evidence of CP violation in the lepton sector. The first half of this talk will give a brief description of neutrino oscillations before presenting the latest neutrino oscillation results from the T2K experiment. The difficulties of neutrino interaction modelling and how this affects oscillation analyses will be discussed before introducing the NuPRISM detector. NuPRISM is an intermediate water Cherenkov detector that continuously samples the neutrino beam across a range of off-axis angles. This detector can remove the problems associated with neutrino interactions by recreating the oscillated far detector spectrum using near detector data. The second half of the talk will describe the NuPRISM analysis method, highlighting the unique abilities of the detector and will present an oscillation analysis that is insensitive to incorrect neutrino interaction modelling.

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Friday 01 July 2016, 16:00: Srubabati Goswami (Physical Research Laboratory, Navrangpura, Ahmedabad)

Probing the Leptonic CP violation in current and future experiments

In this talk I will summarize the current status of the CP phase in the lepton sector. I will discuss the main difficulties associated with the measurement of this parameter. In particular I will discuss the problem of parameter degeneracies. How the synergy between beam based and atmospheric neutrino experiments can help in the determination of the CP phase will be shown. I will also discuss the sensitivity of the DUNE experiment to measure this parameter.

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Friday 17 June 2016, 16:00: Andreas Korn (UCL)

Impressions from DM@LHC2016

I will give my personal impressions from the Dark Matter workshop DM@LHC2016. Slides from my own talk, titled "Latest results in the mono-jet and di-jet channels" will be reused and augmented by selected highlights from a spectrum of other talks.

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Friday 10 June 2016, 16:00: Suchita Kulkarni (HEPHY Viena)

Impact of LHC monojet searches on new physics scenarios

Dark matter searches at the LHC are exploring new models and new regime with every new result. I take a specific example of monojet dark matter searches at the LHC and sketch their impact on two dark matter scenarios. I discuss the complementarity of the results with the direct and indirect detection searches. The two models under considerations are, dark matter motivated explanations of the 750 GeV diphoton excess and dark matter interactions with the Standard Models involving derivative couplings.

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Friday 03 June 2016, 16:00: Miguel Arratia (Cambridge)

"Inelastic proton-proton cross-section at 13 TeV with ATLAS,

The inelastic proton-proton cross-section is a basic property of proton interactions, yet it cannot be calculated from first principles. In 1973 experiments at CERN discovered that it rises with energy—as Heisenberg had predicted. Today, the LHC sets the energy frontier at 13 TeV, and theory predicts an asymptotic “black-disk” limit. In this seminar, I will present a recent measurement of the inelastic cross-section with the ATLAS detector. One of the key ingredients for this study is the rate at which the LHC produces proton collisions—the luminosity. I will illustrate how we measure the LHC luminosity and achieve a percent-level accuracy. Finally, I will describe how this result relates to one of the open questions in cosmic ray physics. "

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Friday 27 May 2016, 16:00: Heidi Sandaker (Oslo)

“The AEGIS experiment”

The AEGIS experiment, situated at the Antimatter Decelerator (AD) at CERN aim to measure for the first time the Earth’s gravitational acceleration of anti-Hydrogen. To achieve this the AEGIS collaboration plan to produce a pulsed cold anti-Hydrogen beam and send it through a classical Moire deflectometer before the anti-Hydrogen is detected by a system of position sensitive detectors. Beyond the gravitational measurements, AEGIS will also provide long-term anti-matter spectroscopy measurements. This talk will present both the scope and current status of the AEGIS experiment as well as discuss future measurements.

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Friday 13 May 2016, 16:00: Kazuki Sakurai (Durham)

“Search for Sphalerons: LHC vs. IceCube"

In a recent paper, Tye and Wong (TW) have argued that sphaleron-induced transitions in high-energy interactions should be enhanced compared to previous calculations, based on a construction of a Bloch wave function in the periodic sphaleron potential and the corresponding pass band structure. In this talk, I present our resent work studying future prospects of observing sphaleron transitions at high energy hadron colliders and IceCube, based on TW results. I first discuss the production rate and possible signatures of the sphaleron-induced processes at high energy hadron colliders. We recast the early ATLAS Run-2 search for microscopic black holes to constrain the rate of sphaleron transitions at 13 TeV LHC. In the second half of the talk, I will discuss the possibility of observing sphaleron transitions induced by cosmogenic neutrinos at IceCube. I calculate the sphaleron event rate at IceCube and discuss the signature of such events. Finally I compare the performance of the sphaleron searches at the LHC and IceCube and find complementarity of these experiments.

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Friday 06 May 2016, 16:00: David Hesketh (Tradinghub)

Financial Rogue Trading and Market Abuse – Finding the Signal in the Noise

The actions of Jerome Kerviel and Kweku Adobole resulted in billion dollar losses for SocGen and UBS. Similarly, the FX and LIBOR scandals have seen banks fined in the hundreds of millions of dollars. This presentation asks why the banks struggle to identify the signals left by these traders. Topics covered include what the traders were doing in each case, the big data statistical approaches used by the anti-terrorist sections of the CIA and MI5 that have been co-opted by the banks and the unique statistical performance metrics used by TradingHub to solve the problem.

The amount of data from various sources: intelligence networks, traffic monitoring, social media, mobile phones, genomics, health etc) data now available for analysis has increased substantially in the last couple of years. However at the same time the requirements on the privacy of the underlying data have become more stringent requiring the need for algorithms to be developed that preserve the privacy of the underlying data while still extracting information with value (economic and otherwise). In this talk the algorithms and methodology being deployed by Privatar will be described.

Jason Mcfall (Privitar)

Privacy in the age of data science

The collection of vast data sets, and the availability huge compute power to analyse them, brings striking new threats to individual privacy. I'll talk through some of the risks and examples of privacy breaches, and survey some promising techniques for protecting data privacy by statistical means, and talk about why this is a hard problem to solve.

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Friday 15 April 2016, 16:00: Richard Amos (UCL/UCLH)

Targeting cancer with proton beams: developments at UCL Hospital

Proton beam therapy (PBT) offers potential clinical advantages over conventional radiotherapy for cancer due to the physical characteristics of charged particle interaction. As protons traverse patient anatomy they lose energy, becoming more densely ionising as they approach their end-of-range, at which point they stop. This manifests into dose deposition as a function of depth that increases to a maximum, the Bragg peak, towards their end-of-range, with no dose beyond. By choosing proton beams of initial energy such that the Bragg peak region is delivered at the depth of the clinical target volume, the therapeutic dose can be realized with reduced dose to surrounding healthy tissue compared to that delivered by photons. Reduced dose to surrounding tissue offers the potential for reduced acute toxicity and secondary cancer risk. These potential clinical advantages have led to a rapid growth in availability of PBT worldwide in recent years and such capability will soon be available at UCL Hospital (UCLH) for NHS patients indicated for protons.

This presentation will describe contemporary PBT technology and practice with particular emphasis given to recent developments and the current status of the UCLH PBT project.

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Friday 08 April 2016, 16:00: Nick Ryder (Oxford)

A SoliD seminar: The SoLid experiment: searching for neutrino oscillations within 10 m from a nuclear reactor

The SoLid collaboration aim to solve the reactor neutrino anomaly by determining whether it is due to oscillations to a new type of `sterile' neutrino. By measuring the anti-neutrino flux as a function of energy and distance between 5 and 10 m from a reactor core, a direct search for oscillations can be performed without relying on flux calculations. I will explain the reactor anomaly and other motivations for our experiment from unexpected structure in the reactor flux spectrum and nuclear safeguards. Performing a neutrino experiment so close to a reactor core presents a number of challenges. I will explain these challenges and the novel, highly segmented, composite scintillator anti-neutrino detector we have developed to overcome them. I will discuss the prototype detectors that we have built and our plans for a phased deployment of our full scale detector starting later this year.

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Friday 18 March 2016, 16:00: Richard Amos (UCL/UCLH) — POSTPONED TO 15/04/2016!

Targeting cancer with proton beams: developments at UCL Hospital

Proton beam therapy (PBT) offers potential clinical advantages over conventional radiotherapy for cancer due to the physical characteristics of charged particle interaction. As protons traverse patient anatomy they lose energy, becoming more densely ionising as they approach their end-of-range, at which point they stop. This manifests into dose deposition as a function of depth that increases to a maximum, the Bragg peak, towards their end-of-range, with no dose beyond. By choosing proton beams of initial energy such that the Bragg peak region is delivered at the depth of the clinical target volume, the therapeutic dose can be realized with reduced dose to surrounding healthy tissue compared to that delivered by photons. Reduced dose to surrounding tissue offers the potential for reduced acute toxicity and secondary cancer risk. These potential clinical advantages have led to a rapid growth in availability of PBT worldwide in recent years and such capability will soon be available at UCL Hospital (UCLH) for NHS patients indicated for protons.

This presentation will describe contemporary PBT technology and practice with particular emphasis given to recent developments and the current status of the UCLH PBT project.

Friday 11 March 2016, 16:00: IOP Practise TALKS!

3rd years!

Exciting new results!

Wednesday 09 March 2016, 16:00: Prof. Chris Done (Durham University)

XXVI SPREADBURY LECTURE: Black Holes - Science fact, fiction or fantasy ?

Black holes are a key plot device in science fiction and fantasy: wormholes through space and time ! In this lecture I'll separate out the fact from the fiction, and talk about how black holes went from a speculative extension of Einstein's gravity to a mainstream observational science via the development of rockets at the start of the space age.

Friday 26 February 2016, 16:00: Chiara Casella (Geneva)

The SAFIR (Small Animal Fast Insert for mRi) experiment

SAFIR - Small Animal Fast Insert for mRi - is a non conventional positron emission tomography (PET) detector for fast and simultaneous hybrid PET/MRI imaging on small animals. The PET detector is designed specifically to be used inside the bore of a commercial 7T pre-clinical magnetic resonance scanner and with ultra short acquisition durations of the order of a few seconds, to enable quantitative dynamic studies of fast biological processes (e.g. blood perfusion and cerebral blood flow with 15O tracers). To compensate for the statistics losses due to the short scan durations, SAFIR will use up to 500 MBq injected activities, one order of magnitude increase with respect to state-of-the-art preclinical systems. Beside the clear MR compatibility, severe important challenges have to be met by the SAFIR detector, mainly in terms of spatial resolution, timing resolution and sensitivity, high number of readout channels, high rate capability per channel and huge data throughput. The detector will rely on matrices of L(Y)SO crystals, optically coupled to SiPM arrays and readout by existing fast readout ASICs. The seminar will describe the SAFIR goal, its concept and the status of the project, with particular emphasis on the characterization measurements of the detector components, including the recent high rate tests performed with different ASICs for the SiPM readout.

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Friday 19 February 2016, 16:00: Uli Haisch (Oxford)

Indirect probes of Higgs effective theory

I review the existing indirect constraints on Wilson coefficients entering the Higgs effective theory. These limits are compared to the direct bounds obtained from LHC and LEP physics.

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Friday 12 February 2016, 16:00: Katharina Bierwagen (MIT)

Measurement of inclusive W/Z production cross sections and CMS performance at sqrt(s)=13 TeV

Precise measurements of W and Z boson production provide an important test of the SM and can be used to further constrain the Parton Distribution Functions. The production of W and Z bosons is well understood in the SM and the clean signatures of the decay particles provide an ideal test bench for the commissioning of the electron, muon and missing energy reconstruction algorithms in the LHC environment. The first results of inclusive W and Z production cross section measurements in pp collisions at sqrt(s)=13 TeV with the CMS detector are presented.

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Friday 05 February 2016, 16:00: Will Barter (CERN)

Recent LHCb measurements of electroweak boson production in Run-1

We present the latest LHCb measurements of forward Electroweak Boson Production using proton-proton collisions recorded in LHC Run-1. The seminar shall discuss measurements of the 8 TeV W & Z boson production cross-sections. These results make use of LHCb's excellent integrated luminosity determination to provide constraints on the parton distribution functions which describe the inner structure of the proton. These LHCb measurements probe a region of phase space at low Bjorken-x where the other LHC experiments have limited sensitivity. We also present measurements of cross-section ratios, and ratios of results in 7 TeV and 8 TeV proton-proton collisions. These results provide precision tests of the Standard Model.

The seminar shall also present a measurement of the forward-backward asymmetry (A_FB) in Z boson decays to two muons. This result allows for precision tests of the vector and axial-vector couplings of the Z boson, providing sensitivity to the effective weak mixing angle (sin^2(theta_W^eff)). The A_FB distribution visible in the LHCb acceptance is particularly sensitive to this angle, as the forward phase-space means that the initial state quark direction is better known than in the central region. This reduces theoretical uncertainties in extracting sin^2(theta_W^eff) from A_FB, and allows LHCb to make the currently most precise determination of sin^2(theta_W^eff) at the LHC.

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Friday 22 January 2016, 16:00: Prof. Andre Schoening (Heidelberg)

The Mu3e Experiment

The Mu3e experiment will search for the Lepton Flavour violating decay mu^+ -> e^+ e^+ e^- with unprecedented sensitivity of 1 out of 10^16 muon decays. This process is heavily suppressed in the Standard Model and any signal would be a clear sign of new physics. The Mu3e experiment is based on the new HV-MAPS detector technology which allows to build ultra-light and fast high resolution pixel detectors.

Friday 15 January 2016, 16:00: Ben Allanach (Cambridge)

Anatomy of the ATLAS diboson excess

I shall discuss some measurements from 8 TeV Run I LHC data that showed an excess over 2 sigma with respect to Standard Model expectations. In particular, we shall review the ATLAS di-boson excess, and show a couple of new physics scenarios that explain the excess. If there is time, I shall then discuss some excesses in CMS data: in a W_R search, in a di-leptoquark search and a new physics explanation that has implications for neutrinoless double beta decay.

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Friday 11 December 2015, 16:00: Dr. Juan Rojo (Oxford)

Reduction strategies for the combination of PDF sets and the PDF4LHC15 recommendations

We discuss recently developed strategies for the statistical combination of PDF sets. These methods allow to combine the predictions of many different PDF sets into a single combined set, in terms of optimized sets of Hessian eigenvectors or Monte Carlo replicas. These combination strategies have been used for the implementation of the 2015 PDF4LHC recommendations, required for the estimation of the total PDF+alphas uncertainties for LHC cross-sections at Run II. We discuss the improvements as compared to the 2011 PDF4LHC prescription, and the impact of the new prescription on precision measurements at Run II.

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Friday 04 December 2015, 16:00: Dr. Sofiane Boucenna (Frascati)

Common Frameworks for DM and Baryogenesis

The nature of dark matter (DM) and the origin of the baryon asymmetry of the Universe (BAU) are two enduring mysteries in particle physics and cosmology. Many approaches have been developed to tackle them simultaneously leading to diverse models and paradigms, such as Asymmetric dark matter (ADM). In the first part of the talk I will give a (brief) overview of what has been done so far, highlighting the important concepts of these constructions. Then, in the second part, I will present a new framework relating the weakly interacting massive particles paradigm to ADM in a minimal and model-independent way.

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Friday 27 November 2015, 16:00: Frank Tackmann (DESY)

XCone: N-jettiness as an Exclusive Cone Jet Algorithm

I will discuss a new jet algorithm XCone, which is based on minimizing the event shape N-jettiness and has several attractive features. It is exclusive and always returns a given fixed number of jets. Well-separated jets are conical and practically identical to anti-kT jets of the same size. Overlapping jets are automatically partitioned by nearest-neighbor. In this way, XCone allows to smoothly transition between the resolved regime where all jets are well separated and the boosted regime where they overlap. It also inherits the theoretical factorization properties of the underlying N- jettiness variable. I will show examples of its application for dijet resonances, Higgs decays to bottom quarks, and all-hadronic top pairs.

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Friday 20 November 2015, 16:00: Katharine Leney (UCL)

Searching for Di-Higgs→bbττ at ATLAS

Several models for new physics predict TeV scale resonances that decay to pairs of Higgs bosons. This talk will review the ATLAS search for pair-produced Higgs bosons decaying to bbττ final states using 20 fb-1 proton-proton collision data with √s = 8 TeV and present the combination of all Run 1 ATLAS di-Higgs searches. I will also review the prospects for di-Higgs searches in the bbττ channel for Run 2 and beyond.

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Friday 13 November 2015, 16:00: Geoff Hall (Imperial)

Tracking and trigger upgrades of CMS

CMS will upgrade its trigger during the forthcoming 13 TeV run to maintain performance under increasingly challenging pileup conditions due to the success of the LHC machine in delivering high luminosity collisions. In the longer term, a new tracker is proposed for installation around 2023, which will for the first time provide data to be used in the L1 trigger. LHC data taking is expected to continue until well into the 2030 decade. The motives for these developments and progress towards them will be explained.

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Friday 06 November 2015, 16:00: Sarah Malik (Imperial)

Review of the status and future prospects of dark matter searches at colliders

Understanding the nature of dark matter is one of the most compelling, long standing questions in physics. Reports of possible dark matter signals from several direct detection experiments have further highlighted the need for independent verification from non-astrophysical experiments, such as colliders. I will review the results of searches for dark matter at CMS in Run 1 of the LHC, what we can expect in Run 2 and beyond, as well as recent developments in dark matter phenomenology.

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Friday 30 October 2015, 16:00: Doug Cowen (Penn State)

High Energy Atmospheric Neutrino Appearance and Disappearance with IceCube

The IceCube neutrino observatory, buried deep in the ice at the South Pole, has detected neutrinos that span over five orders of magnitude in energy. Fulfilling one of its original stated goals of discovering cosmological ultrahigh energy neutrinos, its large instrumented volume also provides us with a surprisingly powerful instrument for studying neutrino oscillations with an unprecedented statistical sample of energetic atmospheric neutrinos. In this presentation we will describe the IceCube detector and focus on its current and future atmospheric neutrino oscillation measurements with DeepCore, IceCube's low-energy in-fill array. We will also describe a new proposed low-energy extension, the Precision IceCube Next Generation Upgrade (PINGU), highlighting its ability to measure one of the remaining fundamental unknowns in particle physics, the neutrino mass hierarchy.

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Friday 23 October 2015, 16:15: Gavin Hesketh (UCL) — Auditorium XLG2 | Christopher Ingold Building

Life after the Higgs: Where next for particle physics?

The Large Hadron Collider, the world's largest particle accelerator, recently restarted after a 2 year break. Smashing protons together at almost twice the energies previously achieved, the data taken next few years may reveal more about the fundamental building blocks of the universe. But, with the discovery of the Higgs Boson in 2012, the theory of these building blocks, the Standard Model, was "completed". So what could we hope to learn next, either at the LHC or elsewhere? http://events.ucl.ac.uk/event/event:hbc-icokdek5-siapwd/life-after-the-higgs-where-next-for-particle-physics

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Friday 16 October 2015, 16:00: Louis Lyons (Oxford/Imperial)

“Statistical Issues in Searches for New Physics

Given the cost, both financial and even more importantly in terms of human effort, in building High Energy Physics accelerators and detectors and running them, it is important to use good statistical techniques in analysing data. This talk covers some of the statistical issues that arise in searches for New Physics. They include topics such as:

• Blind analyses
• Significance
• Should we insist on the 5 sigma criterion for discovery claims?
• $P(A|B)$ is not the same as $P(B|A)$.
• The meaning of $p$-values.
• Example of a problematic likelihood.
• What is Wilks' Theorem and when does it not apply?
• How should we deal with the `Look Elsewhere Effect'?
• Dealing with systematics such as background parametrisation.
• Coverage: What is it and does my method have the correct coverage?
• Combining results, and combining $p$-values
• The use of $p_0$ v $p_1$ plots.

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Friday 09 October 2015, 16:00: Linda Cremonesi (UCL)

Neutrino interactions at the T2K near detector complex

The T2K long-baseline neutrino oscillation experiment observed electron neutrino appearance in 2011 and reported the first results of a search for electron anti-neutrino appearance in 2015. Systematic uncertainties relating to the models of neutrino interactions on atomic nuclei are increasingly problematic as the precision of oscillation measurements improves. Interaction cross-section measurements are therefore vital for the correct interpretation of neutrino data, and consequently reducing the uncertainties on the oscillation measurements. The near detector complex of T2K, with scintillating tracking detectors on-axis (INGRID) and a magnetised fine-grained tracking system off-axis (ND280), offers a unique opportunity to study neutrino interactions in the region of 0.6~1GeV. In this seminar I will report the latest cross-section measurements performed at ND280 and INGRID, which include muon neutrino charged current interactions on different targets (scintillator or water) and with various final states (inclusive, zero pion, one pion and coherent pion production). I will illustrate the value of this data and the difficulties that still remain.

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Thursday 27 August 2015, 16:00: Foteini Oikonomou (Penn State)

Note: Unsual time/date 2pm:
A multi-messenger quest for the sources of the highest energy cosmic rays

The sources of cosmic rays with energy exceeding 10^18 electron volts remain unknown, despite decades of observations. The discovery of the sources of these fascinating cosmic messengers, termed ultra-high energy cosmic rays (UHECRs), will unravel the workings of the Universe's most violent accelerators. I will discuss the constraints imposed by UHECR observations on their sources, focusing on the arrival direction distribution of the UHECRs detected at the Pierre Auger observatory. Constraints on the sources of UHECRs are also imposed by observations of the secondary particles (gamma-rays and neutrinos) that UHECRs produce during their propagation in the intergalactic medium. By way of illustration, I will present models of UHECR emission in blazars, and discuss the detectability of the signatures of such (hadronic) processes in blazar gamma-ray spectra. Finally, I will present the current status of experimental efforts to pin down the origin of UHECRs, by detecting UHECR, neutrino, and electromagnetic transient emission, through real-time coincidence searches, within a global, multi-messenger, alert network.

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Friday 19 June 2015, 16:00: Diego Aristizabal (Université de Liège)

Neutrino masses beyond the tree level

The standard approach to Majorana neutrino masses relies on the type-I seesaw, where neutrino masses are induced through tree level exchange of heavy right-handed neutrinos. Other scenarios, however, are possible and they typically offer testable predictions and in some cases even connections with dark matter. In this talk, after reviewing some well-known loop-induced neutrino mass models, I will discuss a generic approach for two-loop-induced neutrino masses. Finally, I will comment on some possible "generic" accelerator tests of these scenarios.

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Friday 12 June 2015, 16:00: Alex Martyniuk (UCL)

Search for diboson resonances at ATLAS using boson-tagged jets

With the advent of 13TeV proton-proton collisions at the LHC it is natural to trawl through this data searching for new resonances with the highest possible masses. Do we have any clues of what we might expect in this new energy regime? An ATLAS paper released in the dying moments of LHC Run-1* offers us a possible direction. This paper describes a search for a heavy resonance (either a W’ or Kaluza-Klein Graviton) decaying into a diboson pair, leading to highly boosted hadronic jets. By exploiting jet substructure techniques to pick the signal out of the dominant QCD backgrounds the analysis can take advantage of the high branching fraction enjoyed by the fully hadronic decay channel. In this seminar I will describe the jet-substructure techniques explored by the analysis, present the results of the analysis of the 20fb^-1 of 8TeV ATLAS data and finally look to the prospects with the new collision data.

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Friday 05 June 2015, 16:00: Yue-Lin Sming Tsai (IPMU)

Singlet Majorana fermion dark matter: LHC14 and ILC

Exploring a dark matter (DM) candidate using an effective field theory (EFT) framework is a popular approach. However, since the central energy of LHC is going to be 14 TeV and future ILC experiment could also reach 1 TeV, the EFT is not valid any more. In this talk, I will first review our previous work, 1407.1859, then show how we conservatively estimate the power LHC&ILC on EFT by comparing with the UV completed model.

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Friday 29 May 2015, 16:00: Ben Cooper/David Wardrope (UCL)

Searching for new physics with di-Higgs to 4b final states at ATLAS.

It is not often these days that a completely new channel is developed to search for evidence of new physics at the LHC. When Run-1 of the LHC began, the general consensus was that, compared to final states containing leptons, fully hadronic final states would not be competitive in the search for new physics, because the enormous QCD backgrounds would be overwhelming. In this seminar we will tell the story of how this notion was reversed for Higgs pair production, present the latest Run-1 results of the di-Higgs to 4b searches by ATLAS and CMS, and give the prospects for exploiting this channel in the future, including the potential for dramatically extending the physics reach of the HL-LHC.

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Friday 22 May 2015, 12:30: Leigh Whitehead (UCL) — NOTE UNUSUAL TIME

The CHIPS Experiment

CHIPS (Cherenkov Detectors In mine PitS) is an R&D project aiming to blaze the trail towards affordable megaton scale neutrino detectors whilst contributing to the world knowledge on the neutrino mass hierarchy and delta_cp. The first step on the way to this goal was the deployment of CHIPS-M, a small prototype in an open mine pit in northern Minnesota, exposed by the NuMI beam from Fermilab. The second 10 kton prototype, CHIPS-10, is in the design process and is due for deployment in the summer of 2016. CHIPS-10 combined with NOvA and T2K will give over three sigma sensitivity to the mass hierarchy and delta_cp. I will give an overview of the experiment, show the first data from CHIPS-M, and discuss the design of CHIPS-10 and our plans for the future.

Friday 15 May 2015, 16:00: Josef Pradler (HEPHY Vienna)

Dark Vectors in Cosmology and Experiment

More often than not, astrophysical probes are superior to direct laboratory tests when it comes to light, very weekly interacting particles, and it takes clever strategies and/or ultra-pure experimental setups for direct tests to be competitive. In this talk, I will highlight this competition on the example of dark photons. When they are dark matter, direct detection probes can be superior to stellar constraints. When they decay, cosmology offers unique sensitivity through BBN and CMB.

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Thursday 30 April 2015, 16:00: Alain Blondel (Geneva)

CERN: the next 60 years and 100 kilometers

CERN is hosting the design study of Future Circular Colliders fitting in a new tunnel of 100km circumference around Geneva. A possible first step is the "Electroweak Factory", a high luminosity electron-positron (lepton) collider covering the energy range from the Z pole to above the top threshold, for the study of several TeraZ, okuW, MegaHiggs and Megatops. The tunnel would fit, as ultimate goal, a 100 TeV pp collider. The project will be described with special attention to the electron machine. The combination of the two machines offers a remarkable potential for discoveries, from a blend of precision measurements, high statistics, high energies and sensitivity to very small couplings. In particular the search for sterile right-handed neutrinos (aka neutral heavy leptons), with mass up to the Z mass, will be shown to reach couplings as small as predicted by the see-saw limit.

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Friday 17 April 2015, 16:00: Deepak Kar (Glasgow/TBC)

All about showering at the LHSea!

Improving the parton shower model in Monte Carlo generators is important for precision measurements as well as for searches at the LHC. ATLAS and CMS performed many interesting measurements sensitive to to non-perturbative QCD effects and compared the results with existing MC models and tunes, and clear discrepancies and new features have been observed in many cases. All these data are being used in improving the modelling. Also, many jet substructure techniques depend on modelling the shower accurately, and I will briefly discuss one such technique, called shower deconstruction, and the promising results it yields.

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Friday 10 April 2015, 16:00: Cheryl Patrick (NorthWestern)

Neutrino-nucleus interactions at MINERvA

Fermilab's MINERvA experiment is designed to make precision measurements of neutrino scattering cross sections on a variety of materials. After introducing the MINERvA detector, I will explain why these measurements are so important to the current neutrino program. I will then describe several recently published results that are already being used by the neutrino community to improve their modelling of neutrino interactions, focusing particularly on the quasi-elastic analysis. There will also be a chance to look at interesting analyses that will be published in the coming months, and at the plans for MINERvA's longer-term future.

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Friday 27 March 2015, 16:00: UCL HEP Students

IOP practise talks

Note unusual start time: 2pm

Friday 20 March 2015, 16:00: Phillip Litchfield (UCL)

The AlCap experiment // A tour of muon physics from NuFact

The AlCap experiment is a joint project between the COMET and Mu2e collaborations. Both experiments intend to look for the lepton-flavour violating conversion μ+A→e+A, using tertiary muons from high-power pulsed proton beams. In these experiments the products of ordinary muon capture in the muon stopping target are an important concern, both in terms of hit rates in tracking detectors and radiation damage to equipment. The goal of the AlCap experiment is to provide precision measurements of the products of nuclear capture on Aluminium, which is the favoured target material for both COMET and Mu2e. The results will be used for optimising the design of both conversion experiments, and as input to their simulations. Time allowing, I will also present a (necessarily brief) tour of active and planned muon experiments, as presented at NuFact. The muon is something of a special case. Although we know there are three generations of Standard Model particles, the world around us is essentially built up from the first generation. The low mass and correspondingly long lifetime of the muon means that is one of very few higher-generation particles that can be manipulated for study, and as such provides a complimentary window to the standard 'brute force' approach of bringing first-generation particles together at ever higher energies and intensities. I will give a very brief summary of the muon projects discussed at NuFact 2014.

Friday 13 March 2015, 16:00: Jennifer Jentzsch (Dortmund)

Quality assurance measurements during the ATLAS Insertable B-Layer production and integration

The ATLAS Detector is one of the four big particle physics experiments at CERN's LHC. Its inner tracking system consisted of a 3-Layer silicon Pixel Detector (~ 80M readout channels) in the first run (2010-2012) and has been upgraded by an additional layer over the last two years. The Insertable B-Layer (IBL) adds ~12M readout channels for improved vertexing, tracking robustness and b-tagging performance for the upcoming runs before the high luminosity of the LHC will take place. The active part of the detector is roughly 66cm long and consists of 14 parylene coated carbon foam support structures, so-called staves, at an average distance of 33.25mm away from the beam. The IBL includes new sensor and readout chip designs finding their first application in high energy physics experiments. Production accompanying measurements as well as preliminary results after integration into the ATLAS Detector, right before the start of the second LHC run, will be presented and discussed.

Wednesday 11 March 2015, 16:00: Jenny Thomas — Harrie Massey LT

XXV Spreadbury Lecture: Neutrino Oscillations At Work

The observation that the three types of neutrino flavour oscillate among themselves led to the realisation that neutrinos have a very small but non-zero mass. This is extremely important because the supremely successful Standard Model of particle physics had expected, and indeed needed, the neutrinos to have exactly zero mass. Since the discovery of neutrino oscillations over the last 15 years, the parameters of the oscillations have been sufficiently well measured to turn neutrino oscillations into a tool for learning more about the elusive neutrino. I will explain the concept of neutrino oscillations, and report on the recent results from around the world and the new challenges now facing researchers trying to infer the remaining unknown neutrino properties. I will talk briefly about an exciting new project on the horizon for the very near future.

Friday 06 March 2015, 16:00: Freya Blekman (Brussels)

Exploring new physics in the Top quark sector using Beyond-Two-Generations Quarks with the Compact Muon Solenoid

In many models of physics beyond the Standard model the coupling of new physics to third generation quarks is enhanced or signatures are expected that mimic top production. I will present a review of mostly non-MSSM-inspired searches for new physics beyond the standard model in final states containing top quarks or bottom quarks performed by the CMS experiment. Many of these techniques used have solid roots in precision measurements of the standard model, and applying these techniques from measurements to searches has opened a rich and varied searches program in the CMS experiment. Examples include searches for heavy gauge bosons, excited quarks, sequential and vector-like top quark partners. The analyses span a range of final states, from multi-leptonic to entirely hadronic, and many use convoluted analysis techniques to reconstruct the highly boosted final states that are created in these topologies. I will focus on the recent results, using data collected with the CMS experiment in proton-proton collisions at the LHC at a centre-of-mass energy of 8 TeV.

[slides]

Friday 27 February 2015, 16:00: Anastasia Basharina-Freshville (UCL)

Calorimetry for Cancer Proton Therapy - Can We Help?

Proton therapy is an advanced form of radiotherapy that provides significantly improved cancer treatment to patients. In Summer 2015 UCLH will commence the building of a 250 MeV proton beam treatment centre. Challenges currently exist in the field of proton therapy, such as the requirements of precise measurements of the beam energy and spread. We address some of these challenges using a calorimeter module designed for the SuperNEMO experiment, which we have tested at the only currently running proton treatment beam in the UK at the Clatterbridge Centre for Oncology.

[slides]

Friday 20 February 2015, 16:00: Andrea Banfi (Sussex)

A general method for final-state resummations in QCD

We present a novel method that makes it possible to resum event-shape distributions and jet rates at NNLL accuracy. We present results for suitable observables in e+e- annihilation and discuss the generalisation of the method to hadron-hadron collisions and higher logarithmic accuracy.

Friday 13 February 2015, 16:00: Adam Gibson (UCL)

Tracking emissions during proton therapy

Proton radiotherapy uses a beam of protons at up to 250 MeV to deliver a dose of ionising radiation to the body, usually with the intention to cure cancer. The physics of proton interactions with tissue provides a particular advantage: most of the energy is deposited in the Bragg peak, meaning that deeper tissues are largely spared a substantial radiation dose. This reduces the likelihood of side effects, which include an increased risk of cancer later in life. Medical imaging provides excellent knowledge of the internal anatomy of the body, allowing the dose distribution to be precisely predicted. However, patient movement, weight loss and shrinkage of the tumour mean that imaging is not always sufficient to determine the dose distribution delivered. In this talk, I will discuss the physical interactions of the proton beam with tissue, particularly concentrating on the possibility of measuring x-ray, gamma, optical and acoustic emissions so as to predict in real time the distribution of radiation dose to the body.

[slides]

Friday 30 January 2015, 16:00: Simon Bevan/John Loizides

From Particles to Electronic Trading

We will give a detailed overview of the exciting world of FX electronic trading (eFX), detailing the cutting edge technology and mathematics that drive the modern markets. Throughout we will highlight how the skills developed during our stint in HEP translated directly into eFX and why particle physicists are still in such demand.

[slides]

Friday 12 December 2014, 16:00: Teppei Katori (QMUL)

Liquid argon detector R&D in USA

Liquid Argon time projection chamber (LArTPC) is the candidate technology for the next generation large neutrino detectors. Unprecedented resolution and capability of particle ID (ionization energy loss, scintillation light) make it attractive for future high precision neutrino experiments. The necessary technologies were developed by the ICARUS collaboration in Italy and they are further studied in USA. In this talk, I would like to describe the overview of the LArTPC efforts in USA, with a special emphasis on the liquid argon scintillation light detection technology.

[slides]

Friday 05 December 2014, 16:00: Gary Royle (UCL)

Proton and Advanced Radiotherapy

Radiation therapy is a technology based clinical area which uses an array of photons and particles to target cancer sites. It has a number of areas in common with high energy physics. The talk will cover the basis of radiation therapy, the future technological needs, areas where high energy physicists can get involved from research to careers, and will highlight some clinical problems within the treatment of cancer patients that are relevant to the translation of high energy physics concepts and technology.

Monday 01 December 2014, 16:00: Jorge S Diaz (KIT)

Extra ordinary seminar: Testing Lorentz and CPT invariance with neutrinos (NEMO-3 and (Super)NEMO data)

Lorentz symmetry is a cornerstone of modern physics. As the spacetime symmetry of special relativity, Lorentz invariance is a basic component of the standard model of particle physics and general relativity, which to date constitute our most successful descriptions of nature. Deviations from exact symmetry would radically change our view of the universe and current experiments allow us to test the validity of this assumption. In this talk, I will describe how we can search for deviations from exact Lorentz and CPT invariance with neutrino oscillations, time-of-flight measurements, ultra-high-energy neutrinos, and double beta decay.

Friday 28 November 2014, 16:00: Prof. Philip Burrows (Oxford)

Precison Higgs Physics: The International Linear Collider Higgs Factory

An international team has recently completed the Technical Design Report for the International Linear Collider (ILC). The ILC is an electron-positron collider with a design target centre-of-mass energy of 500 GeV. Following the Higgs boson discovery it has been proposed to realise the ILC by building a 250 GeV ‘Higgs Factory’, and subsequently to upgrade it in stages to higher energies of 350 GeV, where it would also serve as a ‘top factory’, and eventually to 500 GeV to allow access to the top-Higgs and Higgs self- couplings. The Japanese particle physics community has proposed to host the collider in Japan. I will describe the programme of precision Higgs-boson measurements at the ILC. I will give an overview of the collider design, and report on the project status.

[slides]

Friday 21 November 2014, 16:00: Richard Savage (Warwick)

Using machine learning to cure cancer (!)

Medicine is undergoing a data revolution. From whole-genome sequencing to digital imaging and electronic health records, new sources of data are promising to revolutionise how we treat disease. With these opportunities, however, come significant challenges. The data are often high-dimensional, noisy, with complex underlying structure. And we may wish to combine multiple data types from very different sources. I'll give a tour of some of these issues, focusing on some of the projects we're working on to use statistical machine learning to get the most out of these data and hence improve, in particular, the treatment and curing of cancer.

Friday 14 November 2014, 16:00: Stuart Mangles (Imperial)

Laser wakefield accelerators: a laboratory source of femtosecond x-ray pulses

Laser wakefield accelerators are now capable of accelerating electron beams up to 1 GeV in just 1 centimetre of plasma. During the acceleration process the electron beam can oscillate, producing very bright femtosecond duration x-rays. In this talk I will introduce some of the key concepts of laser wakefield acceleration and x-ray generation. The x-rays we can generate have some highly useful properties including an ultra short (few femtosecond) duration, micrometer sized source and broad spectral coverage. I will discuss the use of this unique source of x-rays for applications such as probing matter under extreme conditions and medical imaging.

Friday 07 November 2014, 16:00: Cristina Lazzeroni (Birmingham)

Search for rare and forbidden Kaon decays at NA62

The NA62 Kaon programme will be reviewed. A selection of recent results on rare and Standard Model forbidden kaon decays will be presented, and the current status of the experiment and prospects for the measurement of the decay K+ to pi+ nu nubar will be summarised.

[slides]

Friday 31 October 2014, 16:00: Malcolm Fairbarn (Kings College)

Future Dark Matter searches and the Neutrino Background.

I will describe very simple models of dark matter and show how even with reasonable masses, effects such as resonances can lead to very small cross sections at direct detection experiments. I will then briefly discuss the usefulness in slightly more complicated simplified models than the effective operator approach. I will then present some work constraining such models using dijet studies at the LHC and indirect detection and show how direct detection cross sections can be very small in such scenarios, even with good relic abundance. Small cross sections run the risk of being potentially undetectable due to the neutrino background, even with very large future direct detection experiments. I will spend the rest of my talk explaining future strategies for getting the dark matter signal out of the neutrino background.

Friday 17 October 2014, 16:00: Aurélien Benoit-Lévy (UCL)

Inflation, B-modes and dust: Planck's view on BICEP2 results.

The Planck collaboration has recently published new results on the characterisation of polarised dust emission at intermediate and high Galactic latitudes. Although these results specifically focus on the properties of Galactic dust, they are relevant for cosmological studies. Indeed dust is a known contaminant of the long sought-after primordial B modes from Inflation. In this talk, I will focus on how these new results from Planck impact the interpretation of the recent claims from the BICEP2 collaboration.

[slides]

Wednesday 24 September 2014, 16:00: HEP Group Day (E3/E7)

Tuesday 23 September 2014, 16:00: 1st Year PhD Talks (E3/E7)

Thursday 11 September 2014, 16:00: Richard Ruiz (University of Pittsburgh)

State-of-the-Art Tests of Lepton Number Violation and Seesaw Mechanisms at Hadron Colliders

TBA

[slides]

Friday 13 June 2014, 16:00: Prof. Ulrik Egede (Imperial)

Search for HIdden Particles (SHIP) at the SPS

Particles physics faces the contradiction of a Standard Model, that seems perfect and can exist without corrections to the Planck scale, and the inability of the same Standard Model to explain dark matter, neutrino masses and baryogenesis. I will give a brief overview of the vMSM, a minimal extension to the Standard Model that may solve this contradiction. The vMSM predicts the existence of new GeV mass neutral leptons and I will present how a fixed target experiment located at a new beamline of the SPS is ideal to search for these. Possibilities for involvement of UK groups will be discussed.

[slides]

Tuesday 27 May 2014, 14:00: Jouni Suhonen (University of Jyväskylä)

Rare Weak Decays and Nuclear Structure

I will discuss different types of rare decays. I divide these decays in three categories: A. Decays with (ultra) low Q values; B. Decays between states with large differences in the initial and final angular momenta; C. Weak-interaction processes of higher order. The A category contains potential candidates for neutrino-mass measurements in beta decays. Category B highlights cases where single and double beta decays compete. Category C highlights the large variety of different double beta decays that are possible via exchange of a light Majorana neutrino. In particular, the less discussed positron-emission modes of double beta decays, including the interesting resonant neutrinoless double electron capture mode, are elucidated.

Tuesday 27 May 2014, 16:00: Mikhail Shaposhnikov (EPFL)

Higgs inflation at the critical point

Higgs inflation can occur if the Standard Model is a self-consistent effective field theory up to inflationary scale. This leads to a lower bound on the Higgs boson mass, M_h > M_crit. If M_h is more than a few hundreds of MeV above the critical value, the Higgs inflation predicts the universal values of inflationary indexes, r= 0.003 and n_s= 0.97, independently on the Standard Model parameters. We show that in the vicinity of the critical point M_crit the inflationary indexes acquire an essential dependence on the mass of the top quark m_t and M_h, and can be consistent with BICEP 2 data.

Friday 16 May 2014, 16:00: Phillipe Mermod (Geneva)

"Magnetic monopoles at the LHC and in the Cosmos"

Dirac showed in 1931 that the existence of one magnetic monopole in the Universe would explain why electric charge is quantised. The monopole also arises as a natural consequence of Grand Unification theories. While collider experiments provide direct laboratory studies, stable particles with masses beyond the reach of man-made accelerators could have been produced in the early Universe and still be present today. I shall review experimental searches for monopoles at colliders, focusing on recent developments at the LHC. I shall also provide a survey of monopole searches with cosmic-ray detectors and trapped in matter, and propose a few promising avenues for the future.

Friday 09 May 2014, 16:00: Moritz McGarrie (University of the Witwatersrand)

SUSY model building for a 126 GeV Higgs

his talk will review the current status of minimal models of supersymmetry breaking and explore two possible models which can achieve the correct Higgs mass and still allow for sparticles accessible to the LHC's reach. In the first example we use the HEP tool SARAH to build two tailor made spectrum generators to analyse a Higgs extension (non decoupled D-terms) of the MSSM. We then explore the LHC & ILC's capability to determine their effect through their enhancement of Higgs branching ratios with respect to the Standard Model. In the second model, we explore flavour-gauge mediation to obtain light 3rd generation squarks, whilst keeping the 1st and 2nd generation above exclusions. In particular this model can also generate non-degenerate 1st and 2nd generation squarks and, although in the framework of gauge mediation, leads to mild flavour changing neutral currents at, below and above current limits.

Friday 04 April 2014, 16:00: Dimitris Varouchas(LPNHE-Paris)

H -> tautau in ATLAS

In this seminar, a search for the Standard Model (SM) Higgs boson with a mass of 125 GeV decaying into a pair of tau leptons will be reported. The analysis is based on data samples of p-p collisions collected by the ATLAS experiment at the LHC, corresponding to an integrated luminosity of 20.3.0 1/fb at centre-of-mass energy of sqrt(s)=8 TeV. The observed (expected) deviation from the background-only hypothesis corresponds to a significance of 4.1 (3.2) standard deviations, and the measured signal strength is μ = 1.4+0.5 −0.4. This is evidence for the existence of H → τ+τ− decays, consistent with the Standard Model expectation for a Higgs boson with mH = 125 GeV. A brief comparison with the respective CMS result will be also presented.

Friday 28 March 2014, 16:00: UCL third year students — MOVED TO 31/03/2014 !

MOVED! UCL third year student IOP practise talks!

The UCL third year student IOP practise talks will now be on Monday 31/03/2014!

Friday 21 March 2014, 16:00: Prof. Tegid Jones (UCL)

Forty years since the Neutral Current (Z0) Discovery in Gargamelle. The UCL Contribution.

The discovery of neutral currents (1973/74) was the first confirmation of the SU(2)xU(1) electro-weak unified theory. UCL HEP was part of the Gargamelle collaboration which made the first truly significant discovery at CERN. Forty years later the UCL-HEP group contributed to the discovery of the Higgs Boson, thereby completing the understanding of symmetry breaking in the SU(2)xU(1) model.

Friday 14 March 2014, 16:00: Ian P. Shipsey (Oxford)

The Large Synoptic Survey Telescope (for particle physicists)

Recent technological advances have made it possible to carry out deep optical surveys of a large fraction of the visible sky. These surveys enable a diverse array of astronomical and fundamental physics investigations including: the search for small moving objects in the solar system, studies of the assembly history of the Milky Way, the exploration of transient sky, and the establishment of tight constraints on models of dark energy using a variety of independent techniques. The Large Synoptic Survey Telescope (LSST) brings together astrophysicists, particle physicists and computer scientists in the most ambitious project of this kind that has yet been proposed. With an 8.4 m primary mirror, and a 3.2 Gigapixel, 10 square degree CCD camera, LSST will provide nearly an order of magnitude improvement in survey speed over all existing optical surveys, or those which are currently in development. Expected to begin construction later in 2014, and to enter commissioning in 2020, in its first month of operation LSST will survey more of the universe than all previous telescopes built by mankind. Over the full ten years of operation, it will survey half of the sky in six optical colors down to 27th magnitude. Four billion new galaxies and 10 million supernovae will be discovered. At least 800 distinct images will be acquired of every field, enabling a plethora of statistical investigations for intrinsic variability and for control of systematic uncertainties in deep imaging studies. LSST will produce 15 terabytes of data per night, yielding a data set of over 100 petabytes over ten years. Dedicated Computing Facilities will process the image data in near real time, and issue worldwide alerts within 60 seconds for objects that change in position or brightness. In this talk some of the science that will be made possible by the construction of LSST, especially dark energy science, which constitutes a profound challenge to particle physics and cosmology, and an overview of the technical design and current status of the project will be given.

[slides]

Friday 28 February 2014, 16:00: Jo van den Brand (NIKHEF)

Probing dynamical spacetimes

Albert Einstein's theory of general relativity, published in 1915, gave science a radically new way of understanding how space, time and gravity are related. Gravity is defined as the curvature of spacetime and is caused by the four-momentum of matter and radiation. Einstein predicted that accelerating objects will cause vibrations in the fabric of spacetime itself, so-called gravitational waves. The detection of gravitational waves is the most important single discovery to be made in the physics of gravity. Gravitational waves exist in any theory of gravity that incorporates a dynamical gravitational field, be it a metric theory such as general relativity (or one of its generalizations), or a non-metric theory such as string theory. Observations of binary pulsars, whose orbital motion evolves in agreement with general relativity, revealed that gravitational radiation must exist. However, no direct observation of gravitational waves has been reported to date. Discovering gravitational waves would confirm once and for all that gravity is a fundamental dynamical phenomenon. The Virgo detector for gravitational waves consists mainly of a Michelson laser interferometer made of two orthogonal arms being each 3 kilometres long. Virgo is located within the site of EGO, European Gravitational Observatory, based at Cascina, near Pisa on the river Arno plain. Virgo scientists, in collaboration with LIGO in the USA and GEO in Germany, have developed advanced techniques in the field of high power ultra-stable lasers, high reflectivity mirrors, seismic isolation and position and alignment control. In 2015 these collaborations with turn on their advanced instruments in their quest for first detection of gravitational wave events.

Wednesday 26 February 2014, 16:00: George Efstathiou (Cambridge)

SPREADBURY LECTURE (JZ Young LT): The Birth Of The Universe

Modern physics attempts to explain the full complexity of the physical world in terms of three principles: gravity, relativity and quantum mechanics. This raises important fundamental questions such as why is our Universe so large and old? Why is it almost, but not perfectly, homogeneous and isotropic? I will describe how recent measurements of the cosmic microwave background radiation made with the Planck Satellite can be used to answer these questions and to elucidate what happened within 10^-35 seconds of the creation of our Universe.

Friday 21 February 2014, 16:00: Nikos Konstantinidis (UCL)

The High Luminosity LHC programme

As the LHC machine and experiments are preparing frantically to start data taking at design energy and luminosity (and slightly above), an equally intense and exciting programme of R&D and physics studies is ongoing for the High Luminosity (HL-) LHC project, proposed to start in about 10 years, that would deliver 3000/fb to each general purpose detector by the mid-2030s. I will discuss the science case for HL-LHC, the challenges for the accelerator and the experiments, and the ongoing R&D, particularly on the tracking and triggering systems of the experiments

[slides]

Friday 14 February 2014, 16:00: Werner Vogelsang (UNI Tuebingen)

QCD resummation for jet and hadron production

Cross sections for the production of jets or identified hadrons in pp collisions play an important role in particle physics. At colliders, jets are involved in many reactions sensitive to new physics and their backgrounds. In lower-energy collisions, produced hadrons probe the inner structure of the nucleon and the fragmentation process. Both observables have in common that their use crucially relies on our ability to do precision computations of the underlying hard-scattering reactions in QCD perturbation theory. In this talk, we discuss the role of higher-order QCD corrections to these reactions. Specifically, we address the resummation of large logarithmic "threshold" corrections to the relevant partonic cross sections. Among other things, this allows us to determine dominant next-to-next-to-leading order QCD corrections to jet production at the LHC and Tevatron. Detailed phenomenological studies are presented.

[slides]

Friday 07 February 2014, 16:00: Paschal Coyle (In2p3, France)

Neutrinos out of the blue

The road to neutrino astronomy has been long and hard. The recent observation of a diffuse flux of cosmic neutrinos by IceCube heralds just the start of this new astronomy. In this seminar a brief outline of the various experimental efforts worldwide to detect cosmic neutrinos are described and a selection of the physics results presented. Particular emphasis is given to ANTARES, a neutrino telescope located in the deep sea 40km off the southern coast of France. The European neutrino astronomy community has recently started the construction of KM3NeT, a several cubic kilometre neutrino telescope in the Mediterranean Sea. The plans of this new research infrastructure are described. Finally, the potential for a measurement of the neutrino mass hierarchy, with a densely instrumented detector configuration in ice (PINGU) and water (ORCA) is discussed.

[slides]

Friday 31 January 2014, 16:00: Alexander Mitov (Cambridge)

Recent developments in top physics at hadron colliders

I will review the available NNLO results for top pair production at hadron colliders and will demonstrate their effect on various analyses of SM and bSM physics. I will then discuss the prospects for further NNLO level calculations in top physics and how they may influence existing results and open problems in top physics and beyond.

[slides]

Friday 24 January 2014, 16:00: Jennifer Smillie (University of Edinburgh)

Jets, Jets, Higgs & Jets

The LHC is pushing the limits of our theoretical descriptions, especially in multi-jet processes. I will discuss the challenges posed by the large higher-order perturbative corrections, and describe the High Energy Jets framework which provides an alternative all-order description encoding the dominant pieces of the hard-scattering matrix elements. I will illustrate the effectiveness of this method with comparisons to LHC data, and what it teaches us about QCD at the LHC. In the last part of the talk, I will discuss the importance of this in the light of Higgs+dijets studies with an emphasis on vector boson fusion (VBF) channels and will discuss the implications of the previous results. I will show some results from ongoing work to describe the impact of VBF cuts on the gluon-gluon fusion contribution.

[slides]

Friday 13 December 2013, 16:00: Lea Reichhart (UCL)

First results from the LUX Dark Matter Experiment

A vast number of astronomical observation point towards the existence of an unknown dark component dominating the matter content of our Universe. The most compelling candidates for dark matter are the Weakly Interacting Massive Particles (WIMPs), which have great potential to be detected in deep underground low background experiments, looking for direct interactions of WIMPs with dedicated target materials. Very recently, the Large Underground Xenon (LUX) experiment, operated in the Davis Cavern of the SURF laboratory, USA, has announced results from its first science run. From an exposure of 85 days, having found no evidence of signal above expected background, LUX has set constraints on scalar WIMP-nucleon interactions above 7.6x10-46 cm2 at 33 GeV/c2 WIMP mass (90% C.L.) - three times more sensitive than any competing experiment. This first result also seriously challenges the interpretation of hints of signal detected in other experiments as arising from low-mass WIMPs.

Friday 06 December 2013, 16:00: Bryan Lynn (UCL/CERN)

Chiral Symmetry Restoration, Naturalness and the Absence of Higgs-Mass Fine-Tuning 1: Global Theories

The Standard Model (SM), and the scalar sector of its zero-gauge-coupling limit -- the chiral-symmetric limit of the Gell Mann-Levy Model (GML) -- have been shown not to suffer from a Higgs Fine-Tuning (FT) problem due to ultraviolet quadratic divergences (UVQD). In GML all UVQD are absorbed into the mass-squared of pseudo Nambu-Goldstone (pNGB) bosons. Since chiral SU(2)_{L-R} symmetry is restored as the pNGB mass-squared or as the Higgs vacuum expectation value (VEV) are taken to zero, small values of these quantities and of the Higgs mass are natural, and therefore not Fine-Tuned. Our results on the absence of FT also apply to a wide class of high-mass-scale (M_{Heavy}>>m_{Higgs}) extensions to a simplified SO(2) version of GML. We explicitly demonstrate naturalness and no-FT for two examples of heavy physics, both SO(2) singlets: a heavy (M_S >> m_{Higgs}) real scalar field (with or without a VEV); and a right-handed Type 1 See-Saw Majorana neutrino with M_R >> m_{Higgs}. We prove that for |q^2| << M_{Heavy}^2, the heavy degrees of freedom contribute only irrelevant and marginal operators. The crucial common property of such high-mass-scale extensions is that they respect chiral SO(2)_{L-R} symmetry. GML is therefore natural and not FT, not just as a stand-alone renormalizable field theory, but also as a low energy effective theory with certain high-mass-scale extensions. Phenomenological consequences include the renewed possibility of thermal lepto-genesis, and subsequent baryon-number asymmetry, in the neutrino-MSM. We conjecture that, since gravity couples democratically to particles, certain quantum gravitational theories that respect chiral symmetry will also retain low-energy naturalness, and avoid FT problems for GML (and maybe the SM). Absent a SM FT problem, there should be no expectation that LHC will discover physics beyond the SM which is unrelated to neutrino mixing, the only known experimental failure of the SM.

Friday 29 November 2013, 16:00: Matt Lilley (Imperial)

Feeling the Fusion Burn

The age of fusion energy is almost upon us, creating and sustaining hot plasmas of 150 million degrees is now a routine operation performed all around the world. We are ready for next big challenge - the burning plasma - in which the fusion reactions are self sustaining. This is a highly non thermal system which is prone to instability. The nonlinear character of the instability determines the fate of the plasma, either ignition or a mere fizzle. In this presentation we will explore the physical processes behind these burning plasma instabilities and discus the challenges that lie ahead.

[slides]

Friday 22 November 2013, 16:00: Nikos Konstantinidis (UCL) — CANCELED!

The High Luminosity LHC programme

As the LHC machine and experiments are preparing frantically to start data taking at design energy and luminosity (and slightly above), an equally intense and exciting programme of R&D and physics studies is ongoing for the High Luminosity (HL-) LHC project, proposed to start in about 10 years, that would deliver 3000/fb to each general purpose detector by the mid-2030s. I will discuss the science case for HL-LHC, the challenges for the accelerator and the experiments, and the ongoing R&D, particularly on the tracking and triggering systems of the experiments

Friday 15 November 2013, 16:00: TBA

TBA

TBA

Friday 08 November 2013, 16:00: Gabriel Facini (CERN)

H -> bb in ATLAS

Since the discovery of a Higgs-­like boson by the ATLAS and CMS experiments at the LHC, the emphasis has shifted towards measurements of its properties and the search in more challenging channels in order to determine whether the new particle is the Standard Model (SM) Higgs boson. Of particular importance is the direct observation of the coupling of the Higgs boson to fermions. A comprehensive review of the latest ATLAS result in the search for the Higgs boson decaying to a b-­quark pair int associated production channel will be given.

Friday 01 November 2013, 16:00: TBA

TBA

TBA

Friday 25 October 2013, 16:00: Lauren Tompkins (University of Chicago)

FTK: A hardware-based track finder for the ATLAS trigger

The spectacular performance of the LHC machine challenged the ATLAS and CMS detectors to contend with an average of 25 proton-proton interactions per beam crossing in 2012. Projections for 14 TeV running in 2015 and beyond suggest that the detectors should prepare for up to 80 interactions per crossing. In these dense environments, identifying the physics objects of interest, such as isolated leptons, taus and b-jets is of paramount importance for a successful physics program. The ATLAS experiment is developing a hardware based track finder, FTK, which will perform full silicon detector tracking within 100 microseconds of a Level 1 trigger accept at luminosities of 3x10^34 cm^-2 s^-1, significantly improving the track-based isolation, secondary vertex tagging and track-based tau finding done at Level 2. I will discuss the FTK design and performance prospects, as well as report on successful prototype tests completed thus far.

[slides]

Friday 18 October 2013, 16:00: TBA

TBA

TBA

Friday 11 October 2013, 16:00: Bhupal Dev, University of Manchester

Heavy Neutrino Searches at the LHC

One of the simplest extensions of the Standard Model to explain the non-zero neutrino masses is to introduce heavy neutrinos. In this talk, we will review the existing experimental constraints on the masses and mixing of these heavy neutrinos. We will then discuss their ongoing searches at the LHC and some recent efforts to improve their sensitivity.

[slides]

Friday 04 October 2013, 16:00: TBA

TBA

TBA

Tuesday 24 September 2013, 13:00–18.00: 1st Year Student PhD Talks

B05 Lecture Theatre in the Chadwick Building.

Monday 23 September 2013, 13:00–17.00: Group Day + drinks (E1)

B17 (Basement) 1-19 Torrington Place.

Wednesday 18 September 2013, 10:00–17.00: 2nd Year Student PhD Talks

E3/E7 Physics and Astronomy Department.

Thursday 04 July 2013, 16:00: Prof. Jose Valle, (IFIC/CSIC - U. Valencia)

Neutrinos and Dark Matter

I will review the status of neutrino mass and mixing parameters, theoretical modeling and cosmological implications. In particular I discuss how neutrino mass and dark matter may be closely connected and indicate possible direct, indirect and collider detection prospects.

Friday 28 June 2013, 16:00: Brian Rebel, Fermilab

Liquid Argon Detectors at Fermilab: From R&D to LBNE

Liquid argon time projection chambers (LArTPCs) are an exciting new technology for neutrino detectors. This technology provides excellent position resolution that rivals bubble chamber images, but in a digital format. The striking advantage of liquid argon time projection chambers for neutrino physics is the ability to distinguish between electrons, produced in charged current interactions, and gammas, produced by the decay of neutral pions created in neutral current interactions, with high efficiency. This talk will outline the Fermilab R&D program aimed toward development of the multi-kiloton LBNE detector for long baseline neutrino physics. Results from the various aspects of the program will be presented, as well as the status of LBNE.

Wednesday 29 May 2013, 16:00: Alexander Grohsjean, DESY

A quark comes of age: latest highlights in top quark physics.

The discovery of the top quark in 1995 at the Fermilab Tevatron collider was a remarkable confirmation of the standard model of particle physics. Its short lifetime provides the possibility to probe the properties of a bare quark With increasingly large integrated luminosities, the characteristics of this particle, as well as its production and decay properties have been measured with ever greater precision. The analysis of top-quark events triggered the development of new analysis tools and offered an excellent starting point for searches of new phenomena. In this summary, following a short historic perspective, I present recent measurements from the D0 experiment, as well as new ATLAS results from the LHC at 7 and 8 TeV.

Friday 17 May 2013, 16:00: Jonathan Hays, Queen Mary

LHC Higgs results

Last year the ATLAS and CMS experiments announced the discovery of a new particle with a mass of around 126 GeV and a strong candidate for being a Higgs boson. Measurements with the full 2011+2012 dataset have further confirmed this. The latest results in experimental Higgs physics are presented from both experiments, concentrating on the new particle. This includes the continuing search for signals in those modes yet to find evidence for the new particle, property measurements in the diboson modes, and a variety of global fits to data across different channels to investigate compatibility with the Standard Model. Additionally, the compatibility of the results across experiments will be briefly discussed along with some thoughts on the outlook for the Higgs programme at the LHC.

[slides]

Friday 10 May 2013, 16:00: Dr Will Thomas, Centre for the History of Science, Technology and Medicine, Imperial College

Problems in Particle Detection 1930-1950: New Ways to Talk about the History of Physics

Early developments in particle physics were based on the analysis of cosmic rays and radioactive materials before these sources were supplanted by high-energy accelerators circa 1950. Commonly used particle detection technologies included cloud chambers, arrays of coincidence counters, and, after 1945, nuclear emulsions. These technologies all yielded fairly imprecise information about the particles passing through them, necessitating experimenters to deploy strategies to arrive at what they viewed as legitimate interpretations of events. These strategies included using inference to establish what sorts of particles were being detected, the aggregation of evidence, and an increasingly intensive use of nuclear physics knowledge to narrow a range of possible interpretations. It will be suggested that articulating the nature of these strategies, and paying attention to how experimenters deployed them, allows for a good way of discussing historical experimenters’ skill, certainly over and above a simple cataloguing of their discoveries.

[slides]

Friday 03 May 2013, 16:00: Gino Isidori, INFN, Frascati National Laboratories

Standard Model and beyond after the the Higgs discovery

We discuss the implications of the recent Higgs discovery, and particularly of the Higgs mass measurement, for the stability of Higgs potential and, more generally, for the completion of the Standard Model at high energies.

[slides]

Friday 15 March 2013, 16:00: Dr. Bela Majorovits, Max-Planck-Institut für Physik

Understanding Neutrinos?GERDA and the Neutrinoless Double Beta-Decay

Observation of neutrinoless double beta (0vbb) -decay could answer the question whether Neutrinos are their own anti-particles or not and could yield information on the absolute mass scale of neutrinos. The most stringent half-life limit for 76Ge is T1/2>1.9 1025 years. This can be translated to the lowest present limit for the effective Majorana neutrino mass of < 0.3eV. Part of the Heidelberg-Moscow collaboration claims to have observed 0vbb-decay in 76Ge with T1/2=1.2 1025 years, however this result is controversial. A short motivation for 0vbb-decay searches will be given. The principle of 0vbb-searches utilizing High Purity Germanium enriched in the isotope 76Ge detectors will be introduced. The general design features of the GERDA experiment - designed to confirm or refute the claim within one year of measurement will be shown. Results from the GERDA commissioning runs and the status of GERDA data taking with enriched detectors will be discussed. Plans and status of preparations of the second phase of the GERDA experiment will be shown.

[slides]

Friday 08 March 2013, 16:00: Mat Charles, Oxford

Charm results from LHCb

Highlights from LHCb's charm physics programme are presented, including searches for the highly suppressed decays D+ -> pi+ mu- mu+, D+ -> pi- mu+ mu+, and D0 -> mu- mu+; a measurement of meson mixing in D0 -> K+ pi-; and a search for CP violation in two-body D0 decays.

[slides]

Friday 01 March 2013, 16:00: Prof. Chris Mabey, Middlesex Business School

Big Lessons from Big Science

The ATLAS collaboration comprises 3000 physicists from 140 Institutes in 37 countries collaborating on a ‘big science’ project based at CERN near Geneva. As a loosely-coupled, global network of knowledge activists working at the forefront of science, it is prototypical of many knowledge-intensive agencies and firms. What can be learnt from this unusual collaboration about the way tacit knowledge is surfaced and exchanged across professional, cultural and geographic boundaries? ATLAS is feted as a remarkably democratic and highly productive partnership. How does it achieve this and what are the lessons for the effective leadership of knowledge? Chris will share insights from his recent ESRC-funded project (2009-12).

[slides]

Friday 15 February 2013, 16:00: Prof. Robert Thorne, UCL

Parton Distribution Functions at the LHC

I discuss the current status of parton distributions, compare to LHC data and present the range of predictions for LHC processes. Some significant discrepancies are found between different PDF sets, particularly regarding predictions for Higgs boson cross sections and the asymmetry between W^+ and W^- production. I examine possible causes for this, concentrating on issues of parameterisation dependence and the treatment of heavy flavours in the fits.

[slides]

Friday 08 February 2013, 16:00: Dr. Bobby Acharya, Kings College London

Generic Predictions from string/M theory for Particle Physics and Dark Matter

[slides]

Friday 01 February 2013, 16:00: Dr. Ricardo Silva, Department of Statistical Science, UCL

The Structure of the Unobserved

Hidden variables are important components in many multivariate models, as they explain dependencies among recorded variables and may provide a compressed representation of the data. In this talk, I will provide some overview of my line of work on how latent structure can be exploited in machine learning and computational statistics applications. In particular, we will go through the following topics: 1. How to measurement error problems have a causal interpretation and what can potentially be done to identify probabilistic and causal relations among variables that cannot be recorded without error 2. How dependencies among interacting individuals in a network can be explained by hidden common causes and what their roles are in prediction problems 3. How measurements can be compressed into fewer items without losing relevant information from the data, as postulated from a latent variable model, with applications in social sciences

[slides]

Friday 25 January 2013, 16:00: Prof. Buzz Baum, LMCB, UCL

A noisy path to order: refinement of a developing tissue

In my talk I will discuss the process of tissue refinement, whereby an ordered epithelial is generated from an initially disordered state through noisy processes that cause cells to compete for space and fate.

[slides]

Thursday 24 January 2013, 16:00: Jennifer Smillie, (University of Edinburgh)

TBA

TBA

Friday 18 January 2013, 16:00: Dr. Maurizio Piai, Swansea

Holographic techni-dilaton

I review the status of theoretical and phenomenological studies on the holographic techni-dilaton, a light composite scalar present in the spectrum of a class of strongly-coupled models of electroweak symmetry breaking. The experimental signatures of such scalar are similar to those of the Higgs particle of the minimal version of the Standard Model, with important observable differences is some of the search channels. The 125-126 GeV scalar discovered by ATLAS and CMS could be such particle, and I will discuss how to test this hypothesis in future theoretical as well as experimental studies.

[slides]

Friday 11 January 2013, 16:00: Prof. Jon Butterworth, UCL

Standard Model physics

I'll review a selection of LHC measurements of jets, photons and weak bosons, show comparisons to Standard Model predictions, and discuss some lessons learned and future prospects.

[slides]

Friday 14 December 2012, 16:00: Prof. Jeff Forshaw, Manchester

The breakdown of collinear factorization in QCD

Collinear factorization underpins the calculation of many particle physics cross sections, through the use of parton distribution and fragmentation functions. All of the principal Monte Carlo event generators exploit it in their design. In this talk I will explain that in general the factorization does not hold in hadron-hadron collisions and shed light on the mechanism of the breakdown in the language of perturbation theory.

[slides]

Friday 07 December 2012, 16:00: Dr. Stephen West, RHUL

Models of Dark Matter

I will outline some alternatives to the standard neutralino dark matter scenario. In particular, I will review asymmetric dark matter and the production of dark matter via ``freeze-in". I will present the possible ways in which we can search for these candidates in dedicated dark matter search experiments and at colliders.

Friday 30 November 2012, 16:00: Dr. Chamkaur Ghag, UCL

Direct Dark Matter detection

Discovery of the nature of dark matter is internationally recognized as one of the greatest contemporary challenges in science, fundamental to our understanding of the Universe. The most compelling candidates for dark matter are Weakly Interacting Massive Particles (WIMPs) that arise naturally in several models of physics beyond the Standard Model. Although no definitive signal has yet been discovered, the worldwide race towards direct detection has been dramatically accelerated by the progress and evolution of liquid xenon (LXe) time projection chambers (TPCs). The XENON phased programme operates LXeTPCs at Gran Sasso, Italy, and has released results from analysis of 225 days of WIMP search data from the XENON100 detector - presently the most sensitive instrument in the worldwide hunt for WIMPs. XENON100 finds no evidence of signal above expected background and constrains scalar WIMP-nucleon interactions above 2x10-45 cm2 at 55 GeV/c2 WIMP mass (90% C.L.) - over an order of magnitude more stringent than any competing experiment. This result seriously challenges interpretation of the DAMA, CoGeNT or CRESST-II observations as being due to scalar WIMP-nucleon interactions.

[slides]

Friday 23 November 2012, 16:00: Prof. David Evans, Birmingham

Probing the Quark-Gluon Plasma - recent results from ALICE at the LHC

ALICE is a general purpose heavy-ion experiment aimed at studying QCD at extreme energy densities and the properties of the deconfined state of matter, known as a quark-gluon plasma. A selection of the latest results will be presents, together with the first results from proton-lead collisions.

[slides]

Friday 26 October 2012, 16:00: Dr. Simon Jolly

Proton Accelerators for Cancer Therapy

Proton beam therapy (PBT) is a more sophisticated form of radiotherapy for the treatment of cancer. Due to the Bragg Peak, protons can deliver the necessary dose to the tumour site much more precisely than the 6-18 MeV photons used in conventional radiotherapy. This is particularly valuable for tumours in the head and neck and central nervous system and for treating children, whose growing organs need to be protected from excessive dose. Until now proton therapy was only available from the Clatterbridge Centre for Oncology on the Wirral, and then only for eye treatments using 62 MeV protons. Two new sites are planned for the UK to deliver large-scale proton therapy treatment for the first time: at the Christie Hospital in Manchester and at UCL Hospital. I will describe the reasons for using protons over photons and the accelerator technologies used to deliver 70-250 MeV protons for the full range of treatment we will offer at UCLH. I will also cover some of the issues in selecting the right accelerator technology in my role as the accelerator lead for the new UCLH PBT facility and as an advisor to the Christie programme.

[slides]

Friday 19 October 2012, 16:00: Prof. Kael Hanson, Brussels

Particle astrophysics at 90° south: reports from the IceCube Neutrino Observatory

The IceCube Neutrino Observatory is a kilometer-scale cosmic ray muon and neutrino telescope deployed in the deep ice at the South Pole. It detects the Cherenkov radiation emitted by charged particles in transit through the transparent glacial medium by means of a huge array of photomultiplier tubes, each of which independently registers the intensity and arrival time of the radiated photons. The resulting ensemble of hits is processed by event reconstruction algorithms which determine the energy, direction, and type of particle underlying the event. Under construction since 2003, the so-called IC86 array was finally completed December 2010 with the installation of the 86th deep ice string and the full detector was commissioned and placed in operation in May 2011. This talk outlines the science goals of the facility and highlights the results to date that have been released by the IceCube collaboration: searches for high-energy and ultrahigh-energy cosmic neutrinos and lower-energy neutrinos from dark matter; measurements of the cosmic ray anisotropy; detection of neutrino oscillations at high energies. Planned extensions to IceCube are additionally described. Finally, the Askaryan Radio Array (ARA) is introduced. It is an array of radio antennas located next to the current IceCube array which is expected to eventually cover an area of over 100 square kilometers and which targets the detection of the GZK neutrino flux at extreme high-energies which should result from the observed absorption of cosmic rays at these energies.

[slides]

Friday 12 October 2012, 16:00: Dr. Tamsin Edwards, Bristol

Predicting future changes in climate and sea level

How can we predict the future of our planet? I will give an overview of modelling and assessment of uncertainty for future climate change and sea level, focusing on the world-leading UK Climate Projections 2009 and our recent research on Antarctica.

[slides]

Friday 05 October 2012, 16:00: Dr. Kumiko Kotera

From the magnetized Universe to neutrinos: a life of an ultrahigh energy cosmic ray

The origin of ultrahigh energy cosmic rays (UHECRs, particles arriving on the Earth with energy 10^17- 10^21 eV) is still a mystery. I will review the experimental and theoretical efforts that are being deployed by the community to solve this long-standing enigma, including the recent results from the Auger Observatory. I will describe in particular the interactions experienced by UHECRs while propagating from their sources to us, in the cosmic magnetic fields and the various intergalactic backgrounds. These interactions, that induce deflections and multi-messenger production (neutrinos, gamma-rays and gravitational waves) could reveal crucial information about the path taken by these particles, and help us track down their progenitors. I will also focus on one candidate source that has been little discussed in the literature: young rotation-powered pulsars. The production of UHECRs in these objects could give a picture that is surprisingly consistent with the latest data measured with the Auger Observatory.

[slides]

Friday 29 June 2012, 16:00: Prof. Mark Lancaster & Dr. Dave Waters

History of the Tevatron & The Mass of the W Boson

CDF, with significant involvement of the UCL group, have published a W mass measurement with greater precision that all previous measurements combined. We'll take a look at the history of the Tevatron project and particularly the latest ground-breaking W mass measurement. This is an important legacy of the Tevatron as all eyes are now focused on the LHC ...

[slides(Dave),slides(Mark)]

Thursday 14 June 2012, 16:00: Prof. Kam-Biu Luk, University of California at Berkeley and Lawrence Berkeley National Laboratory

Latest results of the Daya Bay Reactor Antineutrino Experiment

The goal of the Daya Bay Reactor Antineutrino Experiment is to determine the neutrino-mixing angle, &theta₁₃, with a precision better than 0.01 in sin²(&theta₁₃). The value of sin²(&theta₁₃) is measured by comparing the observed electron-antineutrino rates and energy spectra with functionally identical detectors located at various baselines from the reactors. This kind of relative measurement using a near-far configuration significantly reduces the systematic errors. Daya Bay began data taking near the end of 2011 and reported the observation of a non-zero value for &theta₁₃ recently. In this seminar, an overview of the experiment and the latest results from Daya Bay will be presented.

[ slides]

Friday 01 June 2012, 16:00: Basil Hiley, Birkbeck College and Rob Flack, UCL

Weak measurement: a new type of quantum measurement and its experimental implications

We will discuss the notion of a ‘weak measurement’, originally introduced by Aharonov et al and carefully analyzed by Duck et al. This technique opens up new experimental possibilities for exploring quantum phenomena. It has already been used to measure the spin Hall effect of light and to measure photon ‘trajectories’ in a two slit interference set up, traditionally deemed to be impossible without destroying the interference effects. We will discuss the theoretical basis for the experimental technique and propose new experiments to explore foundational issues, throwing new light on the Bohm interpretation.

[slides-1, slides-2]

Friday 18 May 2012, 16:00: Dr. Frank Deppisch, UCL

Lepton Flavour and Number Violation in Left-Right Symmetrical Models

We discuss lepton flavour and number violating processes induced in the production and decay of heavy right-handed neutrinos at the Large Hadron Collider. Such particles appear in Left-Right symmetrical extensions of the Standard Model as the "messengers"' of neutrino mass and may have masses of order TeV, potentially accessible at the LHC. We determine the expected sensitivity on the right-handed neutrino mixing matrix, as well as on the right-handed gauge boson and heavy neutrino masses, and compare the results with low-energy probes such as searches for mu-e conversion in nuclei and neutrinoless double beta decay.

[ slides]

Friday 11 May 2012, 16:00: Prof. Max Klein, Liverpool

The LHeC Project at CERN

An overview is given on the physics, detector and accelerator designs of the Large Hadron electron Collider. The LHeC is a new electron- proton/ion collider, which, operating at TeV energy and using the intense LHC p/A beams, is designed to open a new chapter of deep inelastic lepton-hadron physics.

[slides]

Friday 04 May 2012, 16:00: Dr. Marumi Kado, LAL

Higgs searches at the LHC

This talk will give an overview of the searches for the Higgs boson with the ATLAS and CMS detectors at the LHC with the full 2011 dataset, corresponding to an integrated luminosity of nearly 5 fb-1. Both experiments have explored the Higgs boson mass hypotheses range from 110 GeV up to 600 GeV. Most of this range is now excluded at a high confidence level. However, at its low end, for Higgs boson mass hypotheses close to 125 GeV, both experiments observe an excess of events above the background expectation. More data are required to determine the origin of this excess. These results will be reviewed and the short to medium term prospects will be briefly discussed.

[slides]

Friday 27 April 2012, 16:00: Dr. Tracey Berry, Royal Holloway

Searching for Extra Dimensions at ATLAS

The ATLAS experiment at the LHC has been recording data from proton-proton collisions at a centre-of-mass energy of 7 TeV since March 2010. In 2011 it collected an integrated luminosity of over 5 inverse femtobarns. The combination of the large amount of data available and the excellent detector performance has enabled searches for evidence of new physics at this unprecedented energy scale to be performed. In this talk I will give an overview of the ATLAS searches for extra dimensions.

[slides]

Friday 20 April 2012, 16:00: Prof. Mark Lancaster, UCL

The Muon: a probe for new physics

The muon whose discovery in 1937 caused a furore at the time is about to have a renaissance. The availability of new high intensity proton sources at PSI, J-PARC and FNAL will allow the muon's decay modes and dipole moments to be probed to an unprecedented precision. Lepton violation measurements can probe physics far beyond the LHC energy scale and elucidate and resolve degeneracy in new physics models potentially exposed by the LHC. In conjunction with measurements of neutrinoless double beta decay and neutrino oscillations, the muon measurements can also shed light on the mechanism that has generated the universe's matter anti-matter asymmetry. In this talk I will discuss the motivation for, and describe, the next generation of muon experiments and particularly the UK involvement in the COMET experiment.

[slides]

Friday 23 March 2012, 16:00: Dr. Aidan Robson, Glasgow

Final Higgs results from the Tevatron

I will present Higgs search results from the complete Tevatron dataset, which were shown for the first time two weeks ago, and discuss them in the context of recent LHC results.

[slides]

Friday 09 March 2012, 16:00: Dr. Dan Browne, UCL

Putting Bell inequality violation to work

Entanglement and the violation of Bell inequalities are the most striking examples of the incompatibility of quantum physics and the classical world. Quantum experiments can exhibit correlations which would be impossible in any classical world, unless information could travel faster than light. This behaviour is captured by Bell inequalities and other effects. Giving a general introduction to these effects for the non-specialist, I will give examples of the non-classical correlations which can lead to Bell inequality violations and describe how, in my own recent research, Bell inequality violation has been shown to represent something useful - computation.

[slides]

Friday 02 March 2012, 16:00: Dr. Boris Kayser, Fermilab

Neutrino Phenomenology, News, and Questions

We will explain the quantum mechanics of neutrino oscillation, which is a quintessentially quantum mechanical phenomenon. Then we will summarise what has been learned so far about neutrino oscillation experiments and discuss several experimental surprises. Finally, we will turn to the future, focusing on neutrino questions that will be addressed by the search for neutrinoless double beta decay.

[slides(B)]

Friday 24 February 2012, 16:00: Prof. Ben Allanach, Cambridge

LHC versus SUSY

We review what last year's searches mean for supersymmetry, focusing on what they mean in terms of naturalness and fits to indirect data.

[slides]

Friday 17 February 2012, 16:00: Dr. Morgan Wascko, Imperial

T2K's First Neutrino Oscillation Result

The discovery of non-zero neutrino mass, via neutrino flavor oscillation, is the only confirmed observation of physics beyond the standard model of particle physics. Neutrino oscillation experiments have so far measured two of three mixing angles. I will describe the T2K experiment, a long baseline accelerator neutrino experiment in Japan searching for the third mixing angle, and present our first neutrino oscillation results.

[slides]

Friday 10 February 2012, 16:00: Dr. Sarah Bridle, UCL

Quantifying Dark Energy using Cosmic Lensing

I will describe the great potential and possible limitations of using the bending of light by gravity (gravitational lensing) to constrain the mysterious dark energy which seems to dominate the contents of our Universe. In particular we have to remove the blurring effects of our telescopes and the atmosphere to extreme precision, and account for possibly coherent distortions of galaxy shapes due to processes in galaxy formation. I will discuss these issues in more detail and review some recent progress in tackling them, putting them into the context of the upcoming Dark Energy Survey.

[slides]

Friday 03 February 2012, 16:00: Prof. Dmitri Vassiliev, UCL

Is God a geometer or an analyst?

The speaker is a specialist in the analysis of partial differential equations (PDEs) and the talk is an analyst's take on theoretical physics. We address the question: why do all the main equations of theoretical physics such as the Maxwell equation, Dirac equation and the linearized Einstein equation of general relativity contain the same physical constant - the speed of light? The accepted point of view is that this is because our world was designed on the basis of geometry, with the speed of light encoded in the concept of Minkowski metric. We suggest an alternative explanation: electromagnetism, fermions and gravity are different solutions of a single nonlinear hyperbolic system.

[slides]

Friday 27 January 2012, 16:00: Dr. Chris White, Glasgow

Polarisation Studies in Ht and Wt Production

The polarisation of the top quark can be an efficient probe of new physics models. In this seminar, I will focus on the associated production of a single top quark with either a charged Higgs boson or a W boson. Angular and energy observables relating to leptonic decay products of the top will be presented, which carry strong imprints of the top polarisation. These can be used to constrain the parameter space of two Higgs doublet models, as well as reduce backgrounds to either Ht or Wt production. The talk is based on arXiv:1111.0759.

[slides]

Friday 16 December 2011, 16:00: Jenny Thomas

MINOS + MINOS+, so good they named it twice

MINOS has delivered a number of important measurements which have moved the field of neutrino oscillations into the precision arena. The whole field is in a state of heightened excitement with recent results from a number of experiments which point to a large value of he mixing angle theta13. This will enable investigation of the mass hierarchy and CP violation in the experiments which are presently being constructed and being thought about. MINOS+ will be unique in its ability to probe with precision the correctness of the 3x3 PMNS mixing model which is presently assumed to be correct, both via the interference of other models on the oscillation probability over long distances and also via the search for sterile neutrinos, which would imply at least one extra neutrino family. In all cases, the next few years will be a great time for the neutrino field.

Friday 21 October 2011, 16:00: Jocelyn Monroe (Royal Holloway London)

Searching for the Dark Matter Wind: Recent Progress from the DMTPC Experiment

The DMTPC directional dark matter detection experiment is a low-pressure CF4 gas time projection chamber, instrumented with charge and scintillation photon readout. This detector design strategy emphasizes reconstruction of WIMP-induced nuclear recoil tracks, in order to determine the direction of incident dark matter particles. Directional detection has the potential to make a definitive observation of dark matter using the unique angular signature of the dark matter wind, which is distinct from all known backgrounds. This talk will review the experimental technique and current status of DMTPC. 

Friday 07 October 2011, 16:00: Mitesh Patel (Imperial College London)

LHCb

Friday 03 June 2011, 16:00: Luca Panizzi (CNRS-IN2P3)

Lorentz violation in neutrinos from SN 1987a and MINOS

Lorentz invariance can be precisely tested using neutrinos from supernovae or long baseline experiments. I will discuss which limits can be imposed on general phemoneological parametrisations of Lorentz violation which go beyond the usual linear or quadratic power-law behaviour inspired by quantum-gravitational models.

Friday 27 May 2011, 16:00: Costas Andreopoulos (RAL)

First Neutrino Oscillation Results from T2K

T2K is a front-runner, second-generation long-baseline neutrino oscillation experiment. It utilises a new and powerful, relatively pure muon-neutrino beam produced at Japan Proton Accelerator Research Complex (JPARC). The beam is aimed almost 2 degrees off-axis from the position of the Super-Kamiokande water Cherenkov detector in western Japan, 295 km away. The experiment also benefits from a near detector complex, instrumented with finely segmented solid scintillator and TPCs, located 280 m downstream of the beam-line target. The experiment aims to accumulate 8E+21 protons-on-target over the next 5 years. At the end of this running period, T2K aims to have improved present knowledge of sin^{2} (2\theta_{13}), sin^{2} (2\theta_{23}) and \Delta m^{2}_{23} by an order of magnitude. I will present initial muon-neutrino disappearance and electron-neutrino appearance results using the dataset accumulated during the first T2K physics run (January-June 2010), which corresponds to an integrated JPARC neutrino flux exposure of 3.23E+19 protons-on-target.

Friday 20 May 2011, 15:00: Clive Speake (Birmingham) — Maths 505

Experimental Gravitation

I will describe experimental work currently underway at University of Birmingham in gravitation. We are building an experimental test of the inverse square law of gravity at short ranges using a superconducting suspension. I will describe this experiment and the challenges that need to be overcome. We have used a room temperature torsion balance to search for time variations of the gravitational constant over diurnal and semidiurnal periods as predicted by Kostelecky and Tasson (PRL 010402 2009). I will report on recent results from this experiment and improvements that are underway.

Friday 13 May 2011, 16:00: Tony Padilla (Nottingham)

Meddling with Einstein

Einstein gravity has reigned supreme for over 100 years, but is it right? Of course not. We know it is definitely wrong in the super Planckian regime of quantum gravity, but perhaps it is also wrong at very low energies. I give an overview of why we might want to meddle with Einstein, and how we might do so without screwing everything up. I also give a taste of some recent ideas I've had in attempting to "solve" the cosmological constant problem.

Friday 29 April 2011, 16:00: Tony Padilla (Nottingham)

Modified gravity

Friday 15 April 2011, 16:00: Samuel Wallon (Laboratoire de Physique Theorique)

Mueller Navelet Jets

[slides]

Friday 01 April 2011, 16:00: Sam Harper (RAL)

Recent CMS Searches for Gauge Bossons Decaying into High Pt Leptons

Many new physics scenarios beyond the Standard Model predict the existence of new heavy gauge bosons decaying to electrons and muons. Evidence of these new particles has so far not been found experimentally. In 2010, the LHC made available a new energy frontier, significantly extending the potential experimental search region in these channels. In this talk I will briefly motivate these models and then describe the CMS searches for them using 40pb of 7 TeV proton-proton collision data. Finally I will conclude with the outlook for the near term future.

Friday 11 March 2011, 16:00: Matthew Wing (UCL)

Proton Driven Plasma Wakefield Accelerators

Friday 04 March 2011, 16:00: Guennadi Borissov (Lancaster)

Search for new sources of CP violation with DZero detector

I will review the latest results of the DZero experiment on the search for new sources of CP violation and will discuss in detail the measurement of the like-sign dimuon charge asymmetry. This result will be compared with other Tevatron studies of CP violation in Bs system.

Friday 25 February 2011, 16:00: Mario Campanelli (UCL)

Jet Physics at ATLAS

Friday 04 February 2011, 16:00: Gary Barker (University of Warwick)

Liquid Argon Detectors

Friday 17 December 2010, 16:00: John Baines (RAL)

Performance of the ATLAS Trigger in 2010 running

The ATLAS trigger has been used very successfully to collect collision data during 2009 and 2010 LHC running at centre-of-mass energies of 900 GeV, 2.36 TeV, and 7 TeV. The trigger system reduces the event rate, from the design bunch-crossing rate of 40 MHz, to an average recording rate of 200 Hz. The ATLAS trigger is composed of three levels. The first (L1) uses custom electronics to reject most background collisions, in less than 2.5 us, using information from the calorimeter and muon detectors. The upper two trigger levels, known collectively as the High Level Trigger (HLT), are software-based triggers. As well as triggers using global event features, such as missing transverse energy, there are selections based on identifying candidate muons, electrons, photons, tau leptons or jets. I will give an overview of the performance of these trigger selections based on extensive online running during LHC collisions and describe how the trigger has evolved with increasing LHC luminosity. I will end with a brief overview of plans for forthcoming LHC running including future trigger upgrades.

Friday 05 November 2010, 16:00: Justin Evans (UCL)

Latest Results from the MINOS experiment.

The MINOS experiment uses a muon neutrino beam, over a baseline of 735 km, to measure neutrino oscillation parameters. A number of new results have been released this year. The observation of muon neutrino disappearance has allowed the world's most precise measurement of the largest neutrino mass splitting, and a competitive measurement of the mixing angle θ_23. A search for the appearance of electron neutrinos yields limits on the as-yet-unmeasured mixing angle θ_13. A measurement of the neutral current interaction rate allows limits to be placed on the existence of sterile neutrinos. Data has also been taken with a dedicated muon antineutrino beam. This data has been used to make the first precision measurement of the muon antineutrino oscillation parameters; any observed difference from the neutrino parameters would be evidence for physics beyond the standard model.

Friday 29 October 2010, 16:00: Gunther Roland (MIT)

Long-range correlations in high-multiplicity proton-proton collisions at the LHC

The CMS collaboration recently announced the observation of long-range near-side angular correlations in proton-proton collisions at LHC. In this measurement, we have found a novel correlation where particles produced in the collision are aligned in their azimuthal angle over a large pseudorapidity region. This "ridge"-like structure is absent in minimum bias events but emerges as the produced particle multiplicity reaches very high values. This phenomenon has not been observed before in proton-proton collisions but resembles similar effects seen in collisions of nuclei such as copper and gold ions at RHIC. In this talk, I will report on the experimental aspects of this measurement and discuss some of the recent proposals regarding the physical origin of the effect.

Friday 08 October 2010, 16:00: Adam Davison (UCL)

Exciting results from the ICHEP 2010 conference

A review of the exciting results presented at this year's International Conference on High Energy Physics in Paris this summer.

Monday 10 May 2010, 16:00: Subir Sarkar

Antimatter in cosmic rays: new physics or old astrophysics?

There has been considerable excitement generated by recent 'anomalies' in galactic cosmic ray and gamma-ray observations, indicative of dark matter annihilation or decay. It is essential to have a reliable evaluation of the astrophysical 'background' in order to evaluate such claims. I will focus on the PAMELA, Fermi and HESS data and discuss whether these can be accommodated in the 'standard model' of galactic cosmic ray origin and propagation or whether new physics is needed.

Thursday 15 April 2010, 16:00: Krisztian Peters (University of Manchester)

Higgs searches - latest results from the Tevatron

The current status of Standard Model Higgs searches at the Tevatron is presented. A comprehensive program of searches in many Higgs boson production and decay channels is underway, with recent results using up to 5.4/fb of data collected with the CDF and D0 detectors. The major contributing processes include associated production (WH→lνbb, ZH→ννbb, ZH→llbb) and gluon fusion (gg→H→WW). Improvements across the full accessible mass range resulting from the larger data sets, improved analyses techniques and increased signal acceptance will be discussed. A new CDF and D0 combined result with the updated data set will also be presented. Finally, I will discuss prospects for Higgs searches at the Tevatron.

Friday 19 March 2010, 16:00: Steve Biller (University of Oxford)

The SNO+ Project

The continuously surprising and peculiar nature of neutrinos and the weak interaction have been a source of puzzlement since they were first discovered. In recent years, a remarkable paradigm has emerged that seeks to explain hidden symmetries, the scale of neutrino masses and the reason for the imbalance between matter and antimatter in the universe. A cornerstone of this includes the notion that the physical neutrinos we see are their own antiparticles. The only viable mechanism known to have a chance of testing this is the process of neutrinoless double beta decay (0nbb). A pioneering new approach to searching for this rare process involves a novel use of the unique SNO detector in Canada as part of the SNO+ programme, which has a large UK involvement. In concert with other experiments using different isotopes, Phase I aims to convincingly establish or bound 0nbb for equivalent neutrino masses in excess ~100meV and, if seen, constrain the physics mechanism by 2015. Methods to push beyond this are also being explored. In addition, SNO+ will perform precision measurements of solar neutrinos at the transition between matter and vacuum-dominated oscillations to critically test fundamental neutrino couplings as well as studing geo-neutrinos, reactor neutrinos and a variety of other physics.

Friday 12 March 2010, 16:00: Yoshi Uchida (Imperial College London)

Charged Lepton Flavour Violation: a factor one million improvement

Flavour-changing transitions of charged leptons have been a topic of experimental investigation since the early days of particle physics, and this helped shape some of the basic laws that any successful model of particle physics would have to obey, including what we now call the Standard Model. While such phenomena have never been observed to date, when the discovery of neutrino masses and oscillations broke the Standard Model, it transformed the question "Does charged lepton flavour violation exist?" into "How much?" and "How?", and even "Why haven't we seen it yet?". In this seminar, I will describe the current experimental and theoretical state of the field, and why the next generation of experiments could hold the keys that lead the way to a fuller understanding of our universe, offering complementary discoveries that experiments at the high-energy frontier cannot reach. I will then focus on mu-e conversion experimentation, and specifically the COMET/PRISM programme which is promising a sensitivity improvement of four orders of magnitude compared to the current record, potentially improving to six orders, which could open the path to precision measurements with multiple lepton flavour-violating probes of Physics Beyond the Standard Model.

Wednesday 03 March 2010, 16:00: Friedrich Hehl, University of Cologne (M304 Kathleen Lonsdale Building - Origins Seminar)

Nonlocal gravity simulates dark matter

A nonlocal generalization of Einstein's theory of gravitation is constructed within the framework of the translational gauge theory of gravity. In the linear approximation, the nonlocal theory can be interpreted as linearized general relativity but in the presence of dark matter that can be simply expressed as an integral transform of matter. It is shown that this approach can accommodate the Tohline-Kuhn treatment of the astrophysical evidence for dark matter.

Monday 22 February 2010, 16:00: Friedrich Hehl, University of Cologne (Maths room 500 - Origins Seminar)

On the change in form of Maxwell's equations during the last 150 years --- spotlights on the history of classical electrodynamics ---

Starting with Maxwell's equations for the electromagnetic field (1865), we first point out how Maxwell brought his system of equations into quaternionic form. Subsequently, we recognize that what we call Maxwell's equation nowadays is a creation of Heaviside and Hertz. We touch the development of vector calculus (Hamilton, Grassmann, Gibbs, Foeppl) and of tensor calculus (Riemann, Christoffel, Ricci, Levi-Civita) both around 1900. Then we study the impact of special and of general relativity on Maxwell's equations. In particular we follow up the metric-free and topological version of Maxwell's equations via exterior differential forms and period integrals. Some alternative formulations via spinors, Clifford algebras, chains and cochains... are mentioned.

Friday 12 February 2010, 16:00: Jon Butterworth (UCL)

Subjet structure as physics tool at the LHC: and some early LHC Data

I will show some of the first jet data from the 2009 LHC run, and discuss the prospects for using jet substructure to search for new physics in high energy running.

Friday 05 February 2010, 16:00: Adrian Bevan (Queen Mary)

Super Flavour Factories: SuperB

The Standard Model of particle physics is the pinnacle of achievements of science. In one simple model we can describe the behaviour of all known particles extremely well. However we know that there are missing pieces to this puzzle. We can use SuperB to learn about the missing pieces through a multi-prong approach: i) study rare decays, ii) search forbidden decays, and iii) over-constrain measurements of Standard Model sensitive observables to see if they all agree. I will discuss just a few of the many measurements that can be made at SuperB and how these can be used to improve our understanding of particle physics. Having motivated the reasons for a new experiment, I will briefly discuss some of the aspects of such a proposed facility.

Friday 22 January 2010, 16:00: Morgan Wascko (Imperial College London)

Neutrino Cross Section Measurements at SciBooNE

As we enter the era of precision neutrino oscillation measurements, the need to improve neutrino interaction cross section measurements is paramount. SciBooNE at Fermilab uses a fine grained tracking detector to make precise neutrino and antineutrino cross section measurements on carbon and iron. I will present SciBooNE's latest physics results, which are measurement of neutral current neutral pion production by neutrinos. These measurements are of direct relevance to the future global long baseline accelerator neutrino program, especially the T2K experiment in Japan.

Friday 11 December 2009, 16:00: Alain Blondel (University of Geneva)

R&D for neutrino factory and muon collider: the MICE experiment at RAL

Neutrino Factory and Muon Collider are novel accelerators and their development is of great interest for the particle physics community. Producing, capturing and accelerating enough of these particles that live 2.2 microseconds is a challenge at every step. One of the novel technologies is ionization cooling. The Muon Ionization Cooling Experiment at RAL is set to demonstrate the feasibility and performance of a section of cooling channel on a real muon beam. After a brief introduction to the specific virtues of muon colliders and neutrino factory, the MICE experiment and its present status will be described. We will conclude with an invitation to study future possibilities.

Friday 04 December 2009, 16:00: Mark Dorman (UCL)

Preliminary CCQE Neutrino-Nucleus Scattering Results from MINOS

Charged-current quasi-elastic scattering is the dominant neutrino interaction mode at low energies and accurate knowledge of the cross section is important for current and future oscillation experiments. CCQE scattering is also hugely interesting in it's own right as a fundamental process, a probe for the axial nature of the nucleon and a window into the complex world of nuclear effects. I will first introduce the MINOS experiment and discuss CCQE scattering theory and the current status of CCQE cross section measurements. I will then present preliminary results made with a high statistics neutrino scattering dataset collected by the MINOS Near Detector.

[slides]

Friday 06 November 2009, 16:00: Henrique Araujo (Imperial College)

Direct dark matter searches with ZEPLIN-III and beyond

ZEPLIN-III is a two-phase xenon experiment deployed 1100 m underground at the Boulby mine (UK) to search for galactic dark matter WIMPs. These Weakly Interacting Massive Particles are the lead candidate to explain the missing non-baryonic matter in the universe. ZEPLIN-III operates on the principle that electron and nuclear recoils, produced in liquid xenon by different particle species, generate different relative amounts of scintillation light and ionisation charge. WIMPs are expected to scatter elastically off Xe atoms (much like neutrons), and the recoiling atom will produce a different signature to gamma-rays, which create electron recoils. The first science run at Boulby placed a 90%-confidence upper limit on the WIMP-nucleon cross-section of 8.1x10-8 pb, at the level of the world's most sensitive experiments. We are now embarking on the second run after upgrading the instrument and adding an anti-coincidence veto system. With one year of running we expect to improve our sensitivity ten-fold, biting significantly into the parameter space favoured by Supersymmetry. To fully probe the SUSY prediction requires target masses in the tonne scale and above. Achieving this whilst keeping sensitivity to nuclear recoils in the keV scale - and possibly looking for no more than a hand-full of events per year - is a serious technical challenge. This is now the priority for the most competitive technologies, namely cryogenic germanium and the noble liquids. For this next phase we have teamed up with the US LUX collaboration to deploy a tonne-scale xenon target at Homestake (South Dakota, US), possibly followed by a 20-tonne experiment. The nature of dark matter is one the main open questions in Physics today, and the race is on to claim a discovery!

Friday 30 October 2009, 16:00: Mark Lancaster (UCL)

Latest Results from CDF

The latest results from CDF since the spring of 2009, 50 in total, from the world's highest energy collisions (until the LHC beats it by 120 MeV !) at the proton anti-proton Tevatron collider will be presented. These include results on CP anomalies in the b-sector, top quark physics, searches for physics beyond the Standard Model and the latest searches for the Higgs boson.

Friday 16 October 2009, 16:00: Evgueni Goudzovski (University of Birmingham)

A precision test of lepton universality in K --> l nu decays at the CERN NA62 experiment

Measurement of the helicity-suppressed ratio of charged kaon leptonic decay rates BR(K --> e nu)/BR(K --> mu nu) has long been considered as excelent test of lepton universality and the Standard Model description of weak interactions. However it was realised only recently that the helicity suppression enhances the sensitivity to SUSY-induced effects to an experimentally accessible level. The NA62 experiment at CERN has collected a record number of over 10^5 K --> e nu decays during a dedicated run in 2007, aiming at achiving a 0.5% precision. Experimental strategy, details of the analysis, preliminary results, and future prospects of the measurement will be discussed.

[(slides)]

Friday 25 September 2009, 16:00: Geoff Mills (Subatomic Physics Group, Los Alamos National Laboaratory)

Nus and Anti-Nus from MiniBooNE

The MiniBooNE experiment, a short baseline neutrino oscillation experiment currently running at Fermilab, has spent the last two years building up its supply of anti-neutrino data, and has combed through it and the already substantial neutrino data stockpile. The intriguing results will be explored along with future possibilities for short baseline programs.

Friday 07 August 2009, 16:00: Freya Blekman (Cornell University)

CMS Pixel Detector

The Compact Muon Solenoid (CMS) is one of two general purpose experiments at the Large Hadron Collider. The CMS experiment prides itself on an ambitious, all silicon based, tracking system.

After over 10 years of design and construction the CMS tracker detector has been installed and commissioned. The tracker detector consists of ten layers of silicon microstrip detectors while three layers of pixel detector modules are situated closest to the interaction point. The pixel detector consists of 66M pixels of 100um*150um size, and is designed to use the shape of the actual charge distribution of charged particles to gain hit resolutions that will eventually be down to 12 um. This presentation will focus on commissioning activities in the CMS tracker, with extra attention on the pixel detector. Results from cosmic ray studies will be presented, in addition to results obtained from the integration of the detector within the CMS detector and various calibration and alignment analyses.

Friday 05 June 2009, 16:00: Doug Cowen (Pennsylvania State University)

Physics with IceCube's Deep Core Sub-array

The low energy reach of the IceCube Neutrino Observatory will be significantly extended with the addition of a sub-array called "DeepCore." DeepCore will be fully deployed in February 2010 in the clearest ice at the bottom center of the larger array. It will feature a 10x higher pixel density and 40% higher quantum efficiency photomultiplier tubes. It will also benefit greatly from the use of the surrounding IceCube array as an extremely effective veto against the copious background from downward-going cosmic-ray muons.

In this talk we will show that DeepCore extends the energy reach of IceCube to neutrino energies as low as 5-10 GeV. This will allow IceCube to search for lower mass solar WIMP annihilations, astrophysical neutrino sources in the southern sky, and to measure atmospheric neutrino oscillations. After an overview of IceCube and the design and deployment schedule for DeepCore, we will focus on neutrino oscillations with DeepCore. We will present some early results and predictions showing how well we can measure muon neutrino disappearance, how well we might be able to measure tau neutrino appearance, and whether we have a chance to determine the sign of the neutrino hierarchy.

Friday 15 May 2009, 16:00: Mark Dorman (UCL) -- Physics E7

Recent Results from the MINOS Experiment

The MINOS long baseline neutrino oscillation experiment has been taking data in the NuMI neutrino beam since 2005. In this seminar I will introduce the experiment and present the latest physics results from MINOS. I'll first discuss atmospheric neutrino mixing and then present a number of other oscillation results; the search for sterile neutrinos, the search for electron neutrino appearance (theta_13) and anti-neutrino oscillations in MINOS. Finally I'll present neutrino cross section measurements from the Near Detector and summarise the outlook for MINOS.

Friday 08 May 2009, 16:00: Peter Krizan (University of Ljubljana, Jozef Stefan Institute)

From Belle to SuperBelle

The seminar will first review some recent highlights of measurements of B and D meson properties that have been carried out by the Belle collaboration. We will discuss the motivation for a future Super B factory at KEK, as well as the requirements for the detector. Finally, the present status of the project will be presented together with the plans for the future.

Friday 01 May 2009, 15:15: Michela Massimi (UCL) — E7

Are we justified to believe in colored quarks? A philosopher's look at the debate

Friday 24 April 2009, 16:00: Filipe Abdalla (UCL)

Neutrino Mass contstraints from cosmology

Friday 17 April 2009, 16:00: Jim Hinton (Leeds)

Gamma Ray Astronomy

Friday 27 March 2009, 16:00: Are Raklev (University of Cambridge)

Gravitino Dark Matter

Friday 20 March 2009, 16:00: Phil Harris (University of Sussex)

Testing Time Reversal

Friday 13 March 2009, 16:00: Marcella Bona (CERN)

Flavour physics as a test of the SM and a probe of new physics

The vast amount of flavour physics results delivered by the B factories and the Tevatron continuously improving Bs system measurements allows for precision test of the Standard Model (SM). The Unitarity Triangle (UT) analysis for the extraction of the CKM matrix parameters is a powerful tool for combining all the available experimental data in the flavour sector and the lattice QCD calculations to check SM consistency and determine the values of SM observables. The measurements of the UT angles recently performed at B factories provide a determination of the UT comparable in accuracy with the one performed using the other available data. Thus the UT fit is now overconstrained. It is therefore possible to add new physics (NP) contributions to all quantities entering the UT analysis and to perform a combined fit of NP contributions and SM parameters. Thus the UT fit analysis can be turned to a new physics search.

Friday 27 February 2009, 15:00: Gustave Tuck Lecture Theatre

Origins Launch

The keynote speeches will be given by Sir Paul Nurse and Prof. John Ellis.

Wednesday 25 February 2009, 16:00: Tom McLeish

Friday 13 February 2009, 13:30: Maths 706

Origins -- Mathematical Foundations

Friday 23 January 2009, 16:00: Andrej Gorisek

The ATLAS Diamond PIXEL Upgrade

The goal of this project is to construct diamond pixel modules as an option for the ATLAS pixel detector upgrade. This is made possible by progress in three areas: the recent reproducible production of high quality polycrystalline Chemical Vapor Deposition diamond material in wafers, the successful completion and test of the first diamond ATLAS pixel module, and the operation of a diamond after irradiation to 1.8x10^16 p/cm2. I will summarize the results in these three areas and describe our plan to build and characterize a number of ATLAS diamond pixel modules, test their radiation hardness, explore the cooling advantages made available by the high thermal conductivity of diamond and demonstrate industrial viability of bump-bonding of diamond pixel modules.

Friday 05 December 2008, 16:00: Prof. Alain Blondel (University of Geneva)

Status of MICE

Friday 28 November 2008, 16:00: Harry van der Graaf

Alternative ATLAS Upgrade?

Friday 31 October 2008, 16:00: Dr Robert Flack

Results from Neutrino '08

In May 2008 I attended the conference Neutrino08 in Christchurch New Zealand and gave a plenary talk about the latest results from NEMO 3 and SuperNEMO. There were approximately fifty plenary talks and 100 "beer and pizza" talks in the evening. I will give a summary of the main plenary talks.

Friday 24 October 2008, 16:00: Simon Bevan

Ultra High Energy Neutrino Astronomy with ACoRNE

An overview of UHE neutrino astronomy will be presented emphasising on the exciting new results from ACoRNE. The ACoRNE collaboration has successfully been taking data from the Rona array since December 2005. Here the progress in match filters, co-incident pulse finding tools, and neural networks will be discussed, showing the development of a successful reduction and analysis package used on the Rona data. The results of this analysis will be presented as the UK's first acoustic limit.

Friday 17 October 2008, 16:00: Prof. Gary Varner (University of Hawai'i)

Microwave Radio Detection of UHE Air Showers

Extensive air showers deposit such large amounts of energy into the atmosphere that even relatively weak emission mechanisms may be observable at considerable distances. It has been known since the 1960's that UHE Cosmic Ray interactions lead to a concurrent radio emission, though the process was not well understood or characterized at the time. In recent years there has been renewed interest in this lower frequency radio mechanism, attributed to geosynchrotron emission during shower evolution. However since this emission is "beamed" onto the ground, observation is similar to traditional ground array observations of the shower particles. By contrast, in analog to distant shower observation via Nitrogen fluorescence, molecular bremsstrahlung emission of shower electrons leads to isotroptic radiation at microwave radio frequencies. While incoherent emission may be detectable at kilometer scale distances, accelerator measurements indicate that at least partial coherence is present in such cascades, significantly enhancing the fiducial acceptance of this technique. Since the atmosphere is almost completely transparent to microwave and operation is insensitive to light background or weather, an order of magnitude better livetime may be expected compared with fluorescent observation, with potentially lower systematic energy uncertainty. A preliminary satellite dish-based system has been operated in Hawaii and a follow-on prototype system is described that will be deployed at the Auger Observatory in spring 2009.

Friday 10 October 2008, 16:00: Prof. Yoshitaka Kuno (Osaka University)

Physics of Lepton Flavor Violation of Charged Leptons and an Experimental Proposal to Search for Muon to Electron Conversion at J-PARC

Lepton flavor violation of charged leptons has attracted much interest from theorists and experimentalists since it would have potentials to get important hints for new physics beyond the Standard Model, such as SUSY-GUT and/or SUSY-Seesaw models. In particular, a process of muon to electron conversion in a muonic atom is considered to be one of the best to search for. In this talk, a new experimental proposal to search for muon to electron conversion with sensitivity of less than 10^{-16} at J-PARC in Japan will be presented.

Friday 03 October 2008, 16:00: Dr. Chris Hays (University of Oxford)

Search for High-Mass Resonances in CDF Dimuon Data.

Neutral resonances have a long and illustrious history, and could well provide the next big discovery in particle physics. I present a new search for high-mass neutral resonances in the CDF dimuon data, the most sensitive such search to date. The analysis applies the novel technique of probing the inverse mass spectrum, for which the detector resolution is constant in the search region. The results are interpreted in terms of spin 0, 1, and 2 resonances, using sneutrino, Z', and graviton models, respectively.

Friday 26 September 2008, 16:00: Jonathon Coleman (SLAC)

The Status of mixing and CP searches in the charm sector.

During 2007 the Flavor Factories surprised the physics community with unexpected results in charm-mixing. Since this time there has been several confirmations of this phenomena. I will present an overview of recent experimental results from for the $D0$ meson oscillating into its own anti-particle, (or vice versa).

Friday 19 September 2008, 16:00: Fabrizio Palla (INFN-Pisa)

Motivation and possible architechtures for a Level-1 track Trigger in CMS and the SuperLHC

Friday 13 June 2008, 16:00: Carlo Carloni Calame — Maths 500

Electroweak radiative corrections to Drell-Yan processes at hadron colliders

The status of the electro-weak radiative corrections to Drell-Yan processes is summarized. Their impact on observables which are important for Tevatron and LHC physics is discussed. Particular emphasis will be given on their implementation in the event generator Horace.

Friday 30 May 2008, 16:00: Dave Waters (UCL) -- E7

Weighing Up the Weak Force: W Boson Mass and Width Measurements from CDF Run II

The W boson, carrier of the weak nuclear force, is the least well measured of the Standard Model's force carriers. Precision measurements of the mass and the lifetime of the W boson provide a stringent test of the Standard Model and, indirectly, allow us to probe the physics that may lie beyond the Standard Model. I present recent direct measurements of the W boson mass and width from the CDF experiment, both of which are now the single most precise measurements in the world. I discuss several of the challenges involved in performing these analyses, and outline the prospects for such measurements in the future.

Friday 16 May 2008, 16:00: Aidan Robson (University of Glasgow)

Higgs Searches at CDF

2008 is going to be significant for Higgs physics: we expect to reach 95%CL sensitivity to a 160GeV Higgs with the combined Tevatron data. I will talk about CDF's Higgs->WW analysis, focusing on techniques, set it in the context of CDF's low-mass Higgs searches, and give an outlook for the next few years.

Friday 09 May 2008, 16:00: Ken Peach (John Adams Institute for Accelerator Science -- University of Oxford and Royal Holloway University of London)

A new accelerator for advanced research and cancer therapy

Although Fixed-Field Alternating Gradient Accelerators were invented in the 1950s, they have never made any significant impact, the technology being superseded by the synchrotron. However, interest has recently been revived, particularly in Japan, where "proof of principle" proton FFAGs have been built. More recently, a new concept - the "non-scaling FFAG" - has been advanced, which offers the prospect of developing relatively compact, high acceleration rate accelerators for a variety of purposes, from neutrino factories and muon acceleration to cancer therapy. However, there are formidable technical challenges to be overcome, including resonance crossing. We have recently been awarded funding in the UK to construct a demonstrator non-scaling FFAG at the Daresbury laboratory (EMMA, the Electron Model with Many Applications), and to design a prototype machine for proton and carbon ion cancer therapy (PAMELA, the Particle Accelerator for MEdicaL Applications). I will describe some of the motivations for developing this new type of accelerator, and discuss the status of the EMMA and PAMELA projects.

Friday 02 May 2008, 16:00: Terry Sloan (Lancaster University)

Cosmic Rays and Global Warming

In this seminar I will explore the proposed link between changes in cloud cover and the changes in the rate of ionization in the atmosphere produced by the effects of solar magnetic activity on cosmic rays. I will briefly review the mechanism by which this could cause global warming,comparing it with the more conventional view of the cause arising from the increased the concentration of greenhouse gases. I will go on to describe our searches for evidence to corroborate the cosmic ray cloud cover link.

Friday 18 April 2008, 16:00: Fabio Maltoni (Université catholique de Louvain)

The ttbar invariant mass as a window on new physics

I explore in detail the physics potential of a measurement of the ttbar invariant mass distribution at the Tevatron and the LHC. First, the accuracy of the best available predictions for this observable are considered with the result that in the low invariant mass region the shape is very well predicted and could be even used to perform a top mass measurement. Second, I study the effects of an heavy s-channel resonance on the ttbar invariant mass distribution, in a model independent way and outline a simple three-step analysis towards a discovery.

Friday 14 March 2008, 16:00: Fedor Simkovic (Comenius University Bratislava)

Double Beta Decay: History, Present and Future

The properties of the neutrinos have been the most important issues in particle physics, astrophysics and cosmology. After neutrino oscillations discovery, search for neutrinoless double beta decay (0v-decay) represents the new frontiers of neutrino physics, allowing in principle to fix the neutrino mass scale, the neutrino nature (the Dirac or Majorana particles) and possible CP violation effects. Many next generation 0v-decay experiments are in preparation or under consideration. In this presentation the development in the field of nuclear double beta decay is reviewed. A connection of the 0v-decay to neutrino oscillations and other lepton number violating processes is established. The light and sterile neutrino exchange mechanisms as well as R-parity breaking mechanisms of the 0v-decay are analyzed. The problem of the reliable determination of the 0v-decay nuclear matrix elements is addressed. The possibility of boson neutrino and partially boson neutrino is studied in light of the 2v-decay data. The perspectives of the field of the double beta decay are outlined.

Friday 07 March 2008, 16:00: Dr. Tim Namsoo

A prelude to some ZEUS results to be shown at DIS08

The DIS08 conference is fast approaching and is to be hosted by UCL and Oxford University, in the UCL campus in the week starting the 7th April. The ZEUS collaboration, that operated a general purpose detector on the HERA electron-proton collider in Hamburg, and to which the UCL HEP group belongs, are preparing to send a number of results to DIS08. The number and range of these results makes covering them all in a single seminar unfeasible so instead, a subset of results, in which the speaker is involved, will be discussed. These topics will include the measurement of the longitudinal proton structure function, the energy dependence of the photoproduction cross section, studies involving the multiplicity and momentum spectra of charged hadrons in jets and three- and four-jet cross sections in photoproduction. The talk will not include final results on all of these topics but instead will motivate and discuss various aspects of the measurements at a level not possible during the conference itself due to stricter time constraints.

Friday 29 February 2008, 16:00: Dr. Chris Parkes

The LHCb Vertex Locator and the LHCb upgrade - or finishing the bicycle wheel spokes and turning it into a vespa.

LHCb is the dedicated heavy flavour physics experiment at the LHC, and is currently being commissioned. Arguably the single most critical element of the detector is the silicon vertex locator. The unique design has 40 micron pitch silicon strip detectors operated in vacuum only 8mm from the LHC beam and retracted and reinserted between each fill. It is the only LHC detector yet to have seeen beam data - the partially assembled final system having been tested in the CERN SPS. The design, testing, alignment and performance of this detector are discussed. The discovery potential of the experiment, or the measurement of the characteristics of new physics discovered during the first phase, can be significantly enhanced through the upgrade of the experiment to run at higher luminsoity. The plans for the LHCb upgrade are presented.

Friday 22 February 2008, 16:00: Dr. Steve Boyd (Warwick)

T2K - The Next Generation.

It is now a well established fact that the weak and the mass eigenstates of neutrinos are not identical. As a consequence we can observe transitions from one neutrino species to another. Over the past decade neutrino experiments have measured most of the parameters describing neutrino oscillations with ever increasing accuracy. One parameter so far eludes measurement, the so-called mixing angle theta_13. T2K is one of the next generations experiments. While it aims to improve the knowledge of some of the other parameters, its main objective is the measurement of theta_13, which is responsible for muon to electron neutrino transitions. This angle may hold the key to study CP violating effects in the lepton sector of the SM. The seminar will summarise the current status of neutrino oscillation studies, and will outline the future contributions of the T2K Experiment.

Friday 08 February 2008, 16:00: Dr. Lisa Falk-Harris

The Double Chooz Reactor theta_13 Experiment

The Double Chooz reactor experiment is the next step for neutrino oscillation measurements: It will measure, or limit, the last undetermined PMNS mixing angle, theta_13, down to an order of magnitude below the current limit. Deploying two identical detectors, one near the reactor cores and one at a distance of 1.05 km, will permit us to control the systematics to the level required to reach a sensitivity of sin^2 2theta_13 ~0.03. I will give a brief summary of our present knowledge of the neutrino mixing parameters, and a motivation for new reactor experiments. I will then describe the design and status of the Double Chooz experiment and of its detector components. Finally, I will discuss systematics, expected sensitivity and the schedule for installation and data-taking.

Friday 01 February 2008, 16:00: Dr James Libby (Oxford)

The precise determination of the unitarity triangle angle gamma: LHCb and CLEOc

The LHCb experiment will be introduced. The precise determination of gamma is a cornerstone of the LHCb physics programme; the motivation for this will be presented. Decays of the type B+ -> DK+, where the D is a D0 or a D0bar decaying to the same final state, allow a theoretically clean measurement of gamma. The prospects with LHCb for modes where the D decays to 2, 3 and 4 bodies are discussed. This discussions introduces the importance of measurements of the strong parameters of the relevent D-decays to allow precise determination of gamma and the crucial role played by quantum correlated e+e- -> psi(3770) ->D0D0bar data currently being collected by CLEOc. The CLEOc measurements essential to a precise determination of gamma are presented.

Friday 25 January 2008, 16:00: Prof. Stephen Watts (Manchester)

Data Mining and Visualisation

There are more ways to represent ones data than by using graphs, histograms and scatterplots. There are many new techniques which exploit computer technology that enable one to visualise and explore multidimensional data. The seminar will explain these ideas, show how they are related to data mining, and apply them to particle physics data analysis.

Thursday 24 January 2008, 16:00: Prof. Peter Rowson (Stanford Linear Accelerator)

A Novel Approach to Neutrinoless Double Beta Decay - EXO.

The "Enriched Xenon Observatory", or EXO, is an ongoing experimental and R&D program to employ a new technique for the search for neutrinoless double-beta decay. The decay and detection medium is xenon enriched in the 136 isotope. A phase I experiment known as EXO200, using 200 kg of xenon enriched to 80% xenon 136, is presently being installed at the WIPP underground facility in Carlsbad, New Mexico, and is scheduled to begin data taking at the end of the coming summer. In a two year run, this liquid xenon TPC experiment will observe and study two-neutrino double beta decay in xenon for the first time, and should exceed presently available sensitivity for the neutrinoless mode. In parallel, an R&D program is underway for a future multi-tonne detector employing a laser-fluoresence based daughter-nucleus tagging scheme that should be able to reach sensitivities to the effective neutrino mass in neutrinoless double beta-decay down to the 10 meV range.

Friday 18 January 2008, 16:00: Prof. Bob Nichol (Portsmouth)

Seeing Dark Energy

Nearly 10 years ago, astronomers discovered the expansion of the Universe was accelerating driven by a mysterious quantity now know as "Dark Energy". Explaining the existence and properties of dark energy is a major challenge for physicists. In this seminar, I will review the evidence for dark energy (including my own research) and our present understanding of dark energy. I will conclude the talk with an overview of future dark energy research which will dominate cosmology for the next decade.

[slides]

Friday 30 November 2007, 16:00: Borut Kersevan (University of Ljubljana, Jozef Stefan Institute)

AcerMC Monte Carlo Generator and Heavy Flavor Matching

I will present the functionality of the AcerMC Monte Carlo event generator with the emphasis of newly developed procedure for matching hard processes with parton shower approximations in the presence of heavy quarks in the initial state.

Wednesday 14 November 2007, 16:00: Jan Michael Rost

Department Colluquium (Massey Theatre?)

Friday 09 November 2007, 16:00: Prof. Jenny Thomas

Lepton-Photon Neutrino Results

The most exciting results at this years Lepton-Photon came from the neutrino field. I will review the talks giving special attention to Accelerator neutrino Experiments.

Friday 02 November 2007, 16:00: Dr. Chris Hill (Bristol)

Green HEP: Doing Particle Physics with Beam Switched OFF

There are numerous scenarios of physics beyond the Standard Model (e.g. split supersymmetry) which predict the production of a heavy quasi-stable particles in 14 TeV proton-proton collisions. If these particles are charged, they will lose energy via ionisation as they traverse the experimental apparatus. Consequently, if these particles are not produced with too much initial kinetic energy and their lifetime is long enough, they will come to rest in the detector. These "stopped" particles will subsequently decay at some later time, perhaps after the beam has been switched off. I will review the theoretical motivations which suggest that such particles could be copiously produced (and stopped) at the LHC. I will also discuss the status of the experimental effort to search for such particles using the CMS detector.

Friday 19 October 2007, 16:00: Prof. Alan Watson (Leeds)

Recent measurements on ultra-high energy cosmic rays

Knowledge about cosmic rays above 10^19 eV has greatly improved through the successful operation of the Auger Observatory in Argentina where more events above 10^18 eV have now been recorded than from the sum of all previous efforts. I will outline the reasons for interest in this field, describe the Observatory and review our latest results on the mass composition, the energy spectrum and the anisotropy of what are the highest energy particles in Nature.

Wednesday 17 October 2007, 16:00: Don Eigler

The Small Frontier (W.H. Bragg Lecture)

For more than twenty years, the scanning tunneling microscope has given us a kind of virtual presence in the world of atoms. This wonderful instrument not only allows us to "see" the atomic and electronic landscape, but we also can use it to build structures of our own design with individual atoms as the building blocks. In this presentation I will describe how the microscope works and give some examples of how we use it to broaden our knowledge of the physical properties of nanometer-scale structures. I will show examples of our efforts to explore ways in which future computation might be performed using atomic-scale components.

Friday 05 October 2007, 16:00: Prof. Jon Butterworth

Hot (non-neutrino) Results from the EPS Conference

Friday 22 June 2007, 16:00: Sebastian Boeser (UCL)

Towards acoustic detection of ultra-high energy neutrinos

Detection of neutrinos with energies at the far end of the cosmic ray spectrum promises valuable insight not only on cosmological questions, but also for high-energy particle physics. However, the tiny neutrino cross-section and the small flux require target volumes in the order of 100 km^3 - and thus the development of new detection techniques. Among a variety of different target media and interaction signatures, registration of acoustic waves in the South Polar ice cap from the neutrino-induced cascades seems to be promising. The development of a setup to verify the predicted absorption length of ~10km as well as to measure the sound velocity profile and background noise is presented.

Friday 01 June 2007, 16:00: Tim Londergan (Indiana University)

How do we interpret the NuTeV result?

Friday 25 May 2007, 16:00: Tim Gershon (Warwick)

Super Flavour Factory

Recent studies have highlighted the essential role of flavour physics in searching for and understanding physics beyond the Standard Model. At the same time, advances in accelerator technology have made realistic the possibility of an e+e- machine reaching unprecedented luminosities above 1036/cm2/s1. I will summarise the opportunities presented by the SuperB project, as described in the recent Conceptual Design Report.

Friday 18 May 2007, 16:00: Jeppe R. Andersen (Cambridge)

Hard Multi-Jet Predictions from High Energy Factorisation

The dynamics of QCD (and other field theories) simplifies greatly in the so-called perturbative "high energy limit", characterised by large centre of mass energy and fixed (perturbative) transverse scales. We will present a framework based on this high energy factorisation of scattering amplitudes, which allows for the prediction of multi(>=2)-jet rates. We will present predictions for e.g. W+jets, H+jets, and pure n-jet events at the LHC and Tevatron. Finally, we will discuss recent efforts towards improving the accuracy of the calculations.

Friday 04 May 2007, 16:00: Ryan Nichol (UCL)

Ultra-High Energy Neutrino Astronomy in Antarctica

Ultra-high energy neutrino astronomy is a rapidly emerging field at the crossroads of particle physics, astronomy and astrophysics. This talk will address the history and scientific motivation of neutrino astronomy, and discus the detection mechanisms and prospects of current and currently proposed experiments. Particular attention will be paid to the ANITA project, which successfully completed a 35 day flight over Antarctica during the Austral summer of 2006/7.

Friday 20 April 2007, 16:00: Athanasios Dedes (IPPP Durham)

A Natural Nightmare for the LHC

A very simple singlet-extension of the Standard Model which results in naturally light Dirac neutrino masses may also explain the baryon asymmetry of the Universe. This extension requires breaking of a global symmetry associated with neutrinos at low energies which in turn results in a Nambu-Goldstone boson. In this talk I will discuss how the presence of this particle may completely change our view for Higgs boson searches at the LHC.

Friday 30 March 2007, 16:00: Student practice talks for the IoP conference (Details to follow)

Friday 23 March 2007, 16:00: Vladimir Tretyak (Institute for Nuclear Research, Kiev)

Searches for rare decays in nuclear and particle physics in INR

Experiments are reviewed which were performed by the INR (Kiev) group to search for double beta decays of several isotopes, rare alpha and beta decays, and exotic charge non-conserving (CNC) processes like decays of electron, CNC beta decays and disappearance of nucleons. In particular, in the experiment with 116-CdWO_4 crystal scintillators in the Solotvina Underground Laboratory (Ukraine) the two-neutrino double beta decay of 116-Cd was observed (T1/2=2.9e19 yr) and the best limit for neutrinoless double beta decay was set (1.7e23 yr). Fourth-fold forbidden beta decay of 113-Cd was investigated (7.7e15 yr). Rare beta decay of 115-In (4e20 yr) was observed at the first time; probably, it has the lowest value of Q_beta of ~0.5 keV. Two rare alpha decays: of 180-W (1.1e18 yr) and 151-Eu (5e18 yr) were observed at the first time. Limits on exotic decays of electron, nucleons, etc. are mostly the most stringent among known world limits. Experiments were performed either independently or in collaboration with other groups.

Friday 16 March 2007, 16:00: Dr Peter Richardson (Durham)

Herwig++

After a brief recap of the basic physics of Monte Carlo event generators I will describe the development of the new Herwig++ event generator. I will concentrate on recent progress allowing the simulation of hadron-hadron events and physics improvements. I will conclude with our plans for the future.

Sunday 11 March 2007, 16:00: Morgan Wascko (Imperial)

Results from the MiniBoone neutrino experiment

Results from the MiniBoone neutrino experiment, which is investigating the anomalous LSND neutrino oscillation result.

Friday 09 March 2007, 16:00: Prof. Toshimitsu Yamazaki (University of Tokyo and Japan Academy)

Quasi-stable exotic atoms, molecules and nuclei composed of antiproton, pion and kaon

In recent years, unexpectedly long-lived exotic atoms, molecules and nuclei with constituents of antiprotons, negative pion and antikaon have been discovered. The following topics will be covered in this talk: 1) Metastable antiprotonic helium composed of an antiproton, a helium nucleus and an electron as a unique interface between the particle and the antiparticle worlds. High-precision laser spectroscopy for a CPT test and quantum tunneling effect in chemical reactions. 2) Pionic nuclei as a probe for chiral symmetry restoration in nuclear medium. 3) Kaonic nuclear systems as anomalously dense bound states mediated by antikaons. Connection with kaon condensed matter and stars.

Wednesday 07 March 2007, 16:00: Jeff Forshaw

Does there have to be a Higgs boson?

The Large Hadron Collider (LHC) at CERN will soon turn on and it is widely expected to discover the Higgs boson: the particle responsible for the origin of mass and the missing piece in the Standard Model of particle physics. However, there is no guarantee that nature will be so obliging. This talk will explain why we expect to see a Higgs, why it may not be there and why we are so confident that in any event something new should show itself at the LHC.

Friday 02 March 2007, 16:00: Dr Un-ki Yang (Manchester)

Precise Measurements of Top Mass at CDF ( slides )

Tuesday 27 February 2007, 14:00: Dr Olga Mena (Universita "La Sapienza") — Pearson LT in Pearson building

Landscape & Strings in vacqua

I will talk about the high energy neutrino detection capabilities of the long-STRING-Cherenkov Icecube neutrino in ACQUA (ice), sorrounded by the beautiful Antarctica LANDSCAPE. We explore the matter-induced oscillation effects on emitted high energy neutrino fluxes, using the energy dependent ratio of electron and tau induced showers to muon tracks, in the upcoming Icecube neutrino telescope. Although the energy of supernova neutrinos lies far below the threshold for track reconstruction in long-STRING detectors a la Icecube, a supernova neutrino burst could be recorded with a signal-to-noise ratio of ~400. The black hole at the center of the galaxy is a powerful lens for supernova neutrinos. In the very special circumstance of a supernova near the extended line of sight from Earth to the galactic center, lensing could dramatically enhance the neutrino flux at Earth and stretch the neutrino pulse. The Icecube neutrino observatory could be sensitive to both effects.

Friday 23 February 2007, 16:00: Will Venters

A social study of the development and use of Grid for the LHC

Pegasus is a joint research project between the LSE's Information Systems Group and UCL HEP Group to explore the development and use of Grid infrastructure for the LHC. The project is funded by the EPSRC programme: "Usability challenges from e-science" and draws on the LSE group's focus on how information and communication technology influences, and is influenced, by the social context in which it is developed and used as well as by its technical characteristics. Through qualitative research the project is exploring how the variety of people involved in developing and using GridPP infrastructure collaborate. This seminar will introduce the project, its research methods and its expected contribution. We will also outline some of our initial observations from recent research at CERN, and discuss our future research plans.

Friday 16 February 2007, 16:00: Kostas Fountas (Imperial)

The CMS Trigger

Friday 02 February 2007, 16:00: Dr Katherine George (QMUL)

It's not just about B's. Latest Results from BABAR

Friday 19 January 2007, 16:00: Prof. Alan Watson (Leeds)

Progress in the search for the origin of the highest energy cosmic rays

I will explain why there is interest in the highest energy cosmic rays and describe the Pierre Auger Observatory, now the premier instrument available for their study. The latest results on the energy spectrum, mass composition and arrival direction distribution will be discussed and compared with those from other groups. Some speculations about the origin of ultra high energy cosmic rays will be made.

Monday 15 January 2007, 16:00: Doug Gingrich (University of Alberta and TRIUMF)

Very High-Energy Gamma-Ray Astronomy with STACEE

The study of galactic and extragalactic objects using very high-energy gamma rays is an evolving field of science. New gamma-ray telescopes are allowing us to proceed from an era of simply detecting objects to an era of precision measurements of energy spectra and time profiles. Surprisingly, there is still an unexplored energy region of the electromagnetic spectrum: 10 GeV to 250 GeV. The Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) is reaching into this unexplored energy region to observe pulsars, supernova remnants, active galactic nuclei and gamma-ray bursts. My talk will focus on the interest of active galactic nuclei in the unexplored energy region and observations of blazars using STACEE.

Friday 12 January 2007, 16:00: Silvia Capelli (University of Milano)

CUORICINO and CUORE: bolometric experiments for Double Beta Decay research

The positive results obtained in the last few years in neutrino oscillation experiments have stimulated great interest in Neutrinoless Double Beta Decay (DBD0n) research. Cuoricino is a running 40.7 kg TeO2 bolometric experiment dedicated to the search of DBD0n of 130Te atoms.Due to the very low expeted rate for the searched decay, a extremely low level of radioactive background is mandatory, mainly in veiw of the future large mass experiment CUORE, aimed to reach a sensitivity for the neutrino Mayorana mass in the range predicted for an inverse hierarchy scheme for neutrino masses. Last results of CUORICINO and the R&D performed in order toreduce the background level to the wanted sensitivity for CUORE will be presented.

Friday 15 December 2006, 16:00: Dr Bostjan Golob (Ljubljana)

Topics in charm hadron studies at Belle

The Belle detector at the KEK-B e^+e^- B-factory proves to be an excellent experimental environment for a wide variety of measurements. Besides the study of the CP violation in the system of B mesons, various measurements of the properties of charmed hadrons are performed. A short overview of D^0 meson mixing searches, measurements of charmonium-like resonances and properties of the recently observed charm baryons will be given.

Friday 01 December 2006, 16:00: Dr Steve Fitzgerald (Culham)

Fusion energy and nanoscale materials science

I will give a brief overview of the nuclear fusion research at UKAEA Culham, and then discuss some recent work on the modelling of materials for use in the ferocious environment of a fusion reactor.

Friday 24 November 2006, 15:30–17:30: David and Tegid Fest

Speakers include Albrecht Wagner, George Kalmus and David Wark. Refreshments will be provided.

Friday 17 November 2006, 16:00: Dr Cinzia DaVia (Brunel)

3D silicon sensors

The LHC upgrades will demand the innermost layers of the tracking detectors to withstand fluences of about 10^16 n/cm^2 with improved spatial and time resolutions. Forward physics trackers will also require to reduce as much as possible the insensitive area at the detector'e edge. Active edge 3D sensors, where the p and n type electrodes penetrate through the entire silicon bulk thickness, have proven to match these requirements. Results will be reported of their response to charged particles using radioactive sources and particle beams with LHC-compatible readout electronics. The 3D fast time response studied using 0.13 um readout electronics and their signal efficiency after an exposure to reactor neutrons equivalent to ~1.4x10^16 high energy protons per sq. cm. will be discussed.

Friday 03 November 2006, 16:00: Dr Muge Unel (Oxford)

Highlights of PhyStat

The PHYSTAT05 conference held last year in Oxford concentrated on current statistical issues in analyzing data in particle physics, astrophysics and cosmology, as a continuation of the popular PHYSTAT series at CERN (2000), Fermilab (2000), Durham (2002) and Stanford (2003). In-depth discussions on topical issues were presented by leading statisticians and researchers in their relevant fields and the latest, state-of-the-art techniques and facilities were introduced and discussed. I will summarize the conference with an attempt to highlight most of the popular and important topics which are becoming more relevant as the start-up of the LHC experiments approaches.

Slides

Friday 20 October 2006, 16:00: Dr Zornitza Daraktchieva (UCL)

Results from the MUNU experiment on neutrino-electron scattering

The MUNU detector was designed to study electron antineutrino - electron elastic scattering at low energy. The central tracking detector is a Time Projection Chamber filled with CF4 gas, surrounded by an anti-Compton detector. In this talk I will present the final analysis of the data recorded at 3 bar and 1 bar pressure. From the 3-bar data a new upper limit on the neutrino magnetic moment of 9x10^-11 at 90 % C.L. is derived. At 1-bar a Cs-137 photopeak is reconstructed by measuring both the energy and direction of the Compton electrons in the TPC.

Wednesday 18 October 2006: IoP HEPP meeting at UCL

LHC - The first year

The programme and registration details can be found here

Monday 16 October 2006, 16:00: Are Raklev (CERN, Bergen) — E7

Search for Charged Metastable SUSY Particles at the LHC

Friday 06 October 2006, 16:00: Dr Mark Lancaster (UCL)

Hot results from the summer conferences

Wednesday 21 June 2006, 16:00: Joey Huston (MSU)

Lessons from the Tevatron and Standard Model Benchmarks for the LHC

I will discuss results and tools from the Fermilab Tevatron and theapplication of these tools towards the understanding of the Standard Model at the LHC during the early running.

Wednesday 14 June 2006, 17:30: Prof. Jonathan Butterworth (UCL) — Harry Massey amphitheatre

High energy collisions and fundamental physics; or why the proton is like the tardis

Friday 19 May 2006, 16:00: Patricia Vahle (UCL)

Preliminary Results Of An Accelerator Based Search For Muon-Neutrino Disappearance By The MINOS Experiment

Friday 28 April 2006, 16:00: Rick Jesik (Imperial)

Beautifully Strange Physics at DZero

The Tevatron collider experiments have a proven track record for making significant B physics measurements. The hadronic environment provides for the production of B species not readily accessible to the B-factories. One of these states, the Bs meson, is of particular interest. I will report on studies of this meson by the DZero experiment using 1 fb-1 of data. Measurements of the Bs lifetime and lifetime difference, and the first direct upper and lower bounds on the Bs mixing frequency (Delta ms) will be presented. Our measurement of the CP violation parameter in B0 mixing and decay will also be shown.

Friday 07 April 2006, 16:00: Bino Maiheu (UCL)

Hadronization at HERMES

In the HERMES experiment, situated at the HERA storage ring in Hamburg, 27.5 GeV positrons or electrons are scattered off a fixed gaseous, polarised proton target. Data taking started in 1995 and since then HERMES has produced quite some interesting results about the nucleon's internal spin structure. To disentangle the individual contributions from the different quark flavours to the total spin 1/2 of the proton, the understanding of the production of hadrons through fragmentation is very important. Hadrons in HERMES are identified using a Ring Imaging Cherenkov (RICH) detector which is capable to disentangle with high efficiency the different hadron kinds over a momentum range of 2 to 15 GeV/c. By extracting multiplicity distributions we can study the production of hadrons more closely and moreover compare to previously published results at higher energy. Quite some effort was put into obtaining model independent results using an unfolding method to correct for experimental and QED radiative smearing as well as geometrical detector acceptance and efficiency. This talk will highlight some topics of the HERMES physics program with emphasis on the extraction of multiplicity distributions.

Friday 03 March 2006, 16:00: Erkcan Ozcan (UCL)

Radiative Penguin Decays at B Factories

For two decades, radiative penguin decays have played a central role in the search for the "new physics" of the day: top-quark mass, extended TC, anomalous trilinear gauge couplings, fouth generation of quarks and so on. Today, at the brink of the LHC experiments, many phenomenology articles on beyond-the-SM physics, and essentially almost all of the SUSY related ones, again refer to constraints from the radiative penguin decays. In the last few years, the excellent luminosity provided by the B Factories have enabled high-precision measurements of these rare decays. This talk aims to give an overview of the experimental techniques used and current limits obtained, focusing particularly on the inclusive decay b->s\gamma, the most commonly encountered member of the radiative-penguin family in the SUSY literature.

Monday 27 February 2006, 16:00: Carlos Frenk (University of Durham)

Cosmology confronts some of the most fundamental questions in the whole of science. How and when did our universe begin? What is it made of? How did it acquire its current appearance? There has been enormous progress in the past few years towards answering these questions. For example, recent observations have established that our universe contains an unexpected mix of components that include not only ordinary atoms, but also exotic dark matter and a new form of energy called dark energy. Gigantic surveys of galaxies like one recently completed using the Anglo-Australian Telescope in Siding Spring, New South Wales, tell us how the universe is structured. Large supercomputer simulations recreate the evolution of the universe and provide the means to relate processes occuring near the beginning of the Universe with the structures seen today. A coherent picture of cosmic evolution, going back to about a micro-second after the Big Bang, is beginning to emerge. However, fundamental issues, like the nature of the dark energy, remain unresolved. These will require understanding of what went on at even earlier times.

Friday 03 February 2006, 16:00: Ilija Bizjak (UCL)

Measurement of |Vub| at Belle

The measurement of the Cabibbo-Kobayashi-Maskawa matrix element |Vub| is an important counterpart to the measurement of the CP violation parameter sin(2 phi1) in testing the Kobayashi-Maskawa mechanism of CP violation. Recent measurements managed to obtain |Vub| with a precision that is better than 10% and have shown that the theoretical and experimental methods employed can be used to further improve the measurement. I will present the current status of inclusive and exclusive measurements of |Vub| at Belle.

Tuesday 10 January 2006, 16:00: Maury Goodman (Argonne National Laboratory) — in A19

Reactor experiments for neutrino studies

In their simplest form, neutrino oscillations are described by three mixing angles and two differences of mass squared. From solar and atmospheric neutrino experiments, four of the five numbers are approximately known. The fifth value, known as theta-13, is only constrained by an upper limit on its value, which was set by the reactor neutrino experiment CHOOZ. Ideas to measure or further limit this parameter are being pursused by "off-axis" accelerator neutrino experiments, and also by improving reactor neutrino disappearance experiments. Six such reactor experiments are being pursued: Double Chooz, Braidwood, Daya Bay, KASKA, RENO and Angra. The Double Chooz experiment, in a region of France along the Belgian border, will probably be the first one in operation. The prospects and status of this experiment will be described.

Wednesday 07 December 2005, 16:00: James Stirling (IPPP, Durham)

Quantum Chromodynamics and High-Energy Colliders: Fundamental Physics from Non-fundamental Particles

Friday 02 December 2005, 16:00: John Ellis (CERN)

How to look for supersymmetry?

Supersymmetry is still the most promising option for physics beyond the Standard Model, and there are good chances that it could be seen at the LHC. The experimental signature most frequently considered is missing energy, but an interesting alternative is offered by models with a metastable charged particle decaying into gravitino dark matter.

Friday 25 November 2005, 16:00: Charles Loomis (LAL Orsay)

Challenges of Analysis for Grid Computing

The LCG/EGEE production service is the largest operating grid infrastructure in the world. It is currently being used by both HEP and non-HEP applications for large scale productions. However, users wanting to run analyses on the grid will bring higher expectations and more difficult requirements with them. The presentation summarizes the current state of the grid and specific areas which will need to be improved to support analysis on grid infrastructures.

Wednesday 23 November 2005, 16:00: Jens Als-Nielsen (Niels Bohr Institute, Copenhagen)

X-Ray synchrotron radiation - glimpses from the past and of the future

It is well known that synchrotron X-ray science - or maybe more precisely science based on X-ray synchrotron radiation (SR) - has undergone a revolution within the last couple of decades. The brilliance, the figure of merit often used for SR sources, exhibits a growth rate exceeding that of Moore~Rs law for semiconductors, and this development will continue with new large-scale projects such as the free electron X-ray laser. In this talk I shall, however, emphasize another aspect of X-ray science which will have a more direct impact on our daily lives, and that is the proliferation to universities, hospitals and companies of affordable, laser based SR sources equipped with novel X-ray optics. Amongst other benefits, this combination will allow the routine clinical use of phase-contrast imaging rather than conventional absorption-contrast imaging.

Friday 11 November 2005, 16:00: Silvia Pascoli

Determining neutrino masses

In recent years strong evidence of neutrino oscillations has been found. This implies that neutrinos are massive particles. At present, we have measured the solar and atmospheric mass squared differences but the overall neutrino mass scale and the type of hierarchy are still unknown. This information is crucial for our understanding of the origin of neutrino masses. I will review the present knowledge of neutrino parameters. I will discuss the strategies for determining the absolute values of neutrino masses (absolute mass scale and type of hierarchy). In particular, I will focus on neutrinoless double beta decay and long baseline experiments and, briefly, on direct mass searches. I will finally comment on the complementarity of these different approaches.

Friday 04 November 2005, 16:00: Oliver Rosten (Southampton)

Computing in SU(N) Yang-Mills without Fixing the Gauge

A manifestly gauge invariant Exact Renormalisation Group is constructed for SU(N) Yang-Mills, in a form convenient for computation at any loop order. A diagrammatic calculus is developed which facilitates a calculation of the two-loop beta function, for the first time without fixing the gauge or specifying the details of the regularisation scheme.

Wednesday 26 October 2005, 16:00: Steve Jones (UCL)

Did Adam meet Eve? - the view from the genes

Friday 14 October 2005, 16:00: Alan Barr (UCL)

SUSY or extra dimensions? Can we find out with ATLAS?

Two of the most widely talked-about extensions to the Standard Model are supersymmetry and extra spatial dimensions. If applicable at the TeV-scale, both could be discovered at the LHC. However the signals from some extra dimensional models share many of the properties of supersymmetric events. I discuss some recent work which shows that ATLAS has the potential to distinguish between such models.

Friday 07 October 2005, 16:00: Hans Drevermann (CERN)

Data oriented projections in the ATLAS event display ATLANTIS

Based on simulated data of the two inner 3D tracking chambers of ATLAS, it will be shown that special projections of the data allow to check and understand complicated ATLAS interactions. These projections are optimized to suit human perception. The detection of the interactions and the cleaning of high luminosity data sets containing many noisy channels will be demonstrated.

Friday 17 June 2005, 16:00: Georg Weiglein (Durham)

Higgs Physics and Supersymmetry at Present and Future Colliders

Precision tests of the electroweak Standard Model (SM) and its minimal supersymmetric extension (MSSM) are analysed, and indirect constraints on the Higgs-boson mass in the SM and the scale of supersymmetry are discussed. In the MSSM the mass of the lightest Higgs boson is not a free parameter as in the SM, and a firm upper bound can be established. The phenomenology of Higgs physics in the MSSM can differ very significantly from the SM case. The phenomenology of Higgs physics in the MSSM at the Tevatron, the LHC and the ILC is discussed. The possible interplay between the LHC and ILC in analysing the mechanism of electroweak symmetry breaking and the underlying structure of Supersymmetric models is investigated.

Friday 03 June 2005, 16:00: Edwige Tournefier (Annecy)

Gravitational waves and the VIRGO detector

Gravitational waves are predicted by general relativity but have not yet been experimentally observed. A new generation of interferometric experiments aimed at their detection, such as Virgo, is now being commissioned. After an introduction on gravitationnal waves I will give an overview of the world programme before focusing on the Virgo detector and its commissioning.

Tuesday 31 May 2005, 16:00: Wit Busza (MIT)

Surprises from RHIC

Friday 20 May 2005, 16:00: Claire Gwenlan (Oxford)

QCD analyses of HERA data: determination of proton PDFs

Friday 13 May 2005, 16:00: Lucio Cerrito (Oxford)

Top Quark Physics at the Tevatron

The observation of top quarks is still an exclusive privilege of only two experiments operating at the Tevatron Collider. However, never forming bound states, rapidly decaying and with unmeasurably small rare decays the top may appear like a rather uninteresting specie. Or is it ? I will review the latest measurements in top physics at the Tevatron, with focus on the CDF experiment. It emerges a rich programme that is currently testing the Standard Model at the highest energy ever reached in laboratory.

Friday 06 May 2005, 16:00: Simon Dean (UCL)

Once in a lifetime: Investigating Z -> tau tau -> e mu + neutrinos at D0

The sum of signed impact parameters in a two-track system is proposed as a tool for discriminating channels with lifetime in the final state. Z ->tau tau -> e mu is shown to be a realistic process for demonstrating this effect and a signal sample is selected from the D0 RunII dataset.

Friday 22 April 2005, 16:00: Emily Nurse (UCL)

Electroweak physics at the Tevatron

Run II of the Tevatron is now well underway and results are starting to come out thick and fast. I will present the recent electroweak results from CDF and Dzero, going through one analysis in detail to give some insight into how precision measurements are done at hadron colliders.

Friday 15 April 2005, 16:00: Philip Burrows (QMUL)

The Linear Collider: microscope on physics at the TeV scale

I will discuss the power of the Linear Collider in terms of precision measurements and discovery potential for new physics at the TeV scale. I will discuss the joint potential of the Linear Collider and the LHC. I will review briefly the status of the International Linear Collider project and the UK contributions.

Monday 04 April 2005, 16:00: Chris Quigg (FermiLab)

The Double Simplex; envisioning particles and interactions

Tuesday 01 March 2005, 16:00: Glen Marshall

Recent results from the TWIST experiment

The TRIUMF Weak Interaction Symmetry Test (TWIST) has recently completed its first physics analyses. The results represent a significant increase in precision for two of the four Michel parameters describing the energy and angle distributions of positrons from polarized positive muon decay. This is the first step toward our eventual goal of improving upon previous determinations for three of the parameters by at least an order of magnitude, as a test the Standard Model in the purely leptonic decay interaction. TWIST uses a polarized muon beam stopping at the center of a spectrometer consisting of a low mass, high precision array of planar drift chambers in a two tesla solenoidal field. The talk will focus on the operation of the device and the methods which are used to extract the decay parameters in a reliable way. Systematic uncertainties are especially important, as they will limit the final results.

Friday 25 February 2005, 16:00: Yoshi Uchida

The KamLAND experiment

Friday 18 February 2005, 16:00: Hans Kraus (Oxford)

The CRESST Dark Matter Search

Dark Matter is one of the key issues in the field of particle-astrophysics. We understand many phenomena in great detail, but yet, we do not know what the bulk of the Universe is made of. Dark Matter and Dark Energy appear to dominate normal matter by a large factor. I summarize the astrophysics evidence we have for the existence of Dark Matter; explain how particle physics provides a good candidate for Dark Matter particles and talk about the experimental challenges one has to master in attempting to detect WIMP Dark Matter. I review the general requirements every Dark Matter experiment has to satisfy and summarize some of the physics carried out within underground laboratories. The focus of the presentation is on novel cryogenic detectors that CRESST uses to search for WIMPs. These detectors are scintillating low-temperature calorimeters operating in the milli-kelvin temperature range and providing event type recognition to distinguish between a potential signal and backgrounds. The presentation concludes with a summary on how far the world-wide search for Dark Matter has progressed.

Friday 04 February 2005, 16:00: Steward Boogert (UCL)

Physics of/at a linear e+ e- collider

Friday 28 January 2005, 16:00: Philip Harris (Sussex)

The neutron EDM experiment

Friday 03 December 2004, 16:00: Jon Butterworth (UCL)

Implications of HERA measurements for the LHC

Friday 26 November 2004, 16:00: Ofer Lahav (UCL)

Neutrinos and Cosmology

Friday 19 November 2004, 16:00: Bill Murray (RAL)

Results from MuScat

Ionization cooling is foreseen for the muon collider and neutrino factory, and is to be tested in action in the Mice experiment at RAL. The cooling effect of dedx losses is offset by multiple scattering, which is difficult to calculate and has not been measured at the appropriate muon momenta. The MuScat experiment fixes that deficiency. The results of the MuScat experiment are presented, along with details of the performance.

Friday 15 October 2004, 16:00: David Miller (UCL)

Physics at the Future Linear Collider

Friday 08 October 2004, 16:00: Nikos Konstantinidis (UCL)

The Higgs Search: Past, present and future

Almost four years after the last data from LEP, (preparation for) the search for the wholy grail of particle physics continues. Starting with a quick review of LEP's legendary contribution to the Higgs searches, I will discuss (a) the more recent progress in precision electroweak measurements and the information they provide for the SM Higgs; and (b) the expectations in the coming years from the Tevatron and the LHC.

Friday 04 June 2004, 16:00: David Evans (Birmingham)

"ALICE and the Physics of Quark Matter"

QCD predicts that hadronic matter, under extreme conditions of temperature and pressure, will undergo a phase transition into a deconfined soup of quarks and gluons called a Quark-Gluon Plasma (QGP) The University would have been in such a state some 10^-6 to 10^-5 seconds after the Big Bang. Colliding lead ions at LHC energies will produce such a QGP and the ALICE experiment will study QCD in detail under these extreme conditions.

Friday 28 May 2004, 16:00: Costas Andreopoulos (RAL)

"The MINOS experiment: Just 7 months away from the first beam event!"

MINOS is a first generation long baseline neutrino oscillation experiment designed to study the oscillation parameter space hinted at by the results of atmospheric neutrino experiments. In order to achieve this goal we plan to use two magnetized iron calorimeters with solid scintillator as active material: a 5.4 kt one in Soudan mine in Minnesota, 735 km away from an intense, low energy neutrino beam source at Fermilab, and a smaller 1 kt one just 1 km downstream of the neutrino source. Neutrino oscillation measurements will be carried on by comparing the neutrino event rates and spectra at the two detectors. In this talk, I will briefly summarize the current experimental evidence for neutrino oscillations and describe the current status of the MINOS experiment which is now very close to the end of its construction phase. I will also try to illustrate what challenges we are going to face, after the beam starts up, using highlights from my recent work in event reconstruction, event classification and neutrino interaction model tuning/validation.

Friday 21 May 2004, 16:00: Simon Dean (Manchester)

"Once in a Lifetime: Investigating Z -> tau tau -> e mu (+neutrinos) at D0"

The sum of signed impact parameters in a two-track system is proposed as a tool for discriminating channels with lifetime in the final state. Z -> tau tau -> e mu is shown to be a realistic process for studying this effect and the current best method of signal selection is presented

Friday 27 February 2004, 16:00: Todd Huffman, Oxford

"Why B Physics is Interesting, (with a CDF focus)"

We all are convinced that the Standard Model of particle interactions is not the last word in the theory of the fundamental forces of nature. There are many searches proposed and on-going to try to add data to the speculations of what lies beyond the Standard Model. I show that the study of B mesons is actually much more fascinating than the simple measurements of lifetimes and branching ratios. These particles probe some very basic questions about the nature of matter in the Universe and are already beginning to constrain the physics beyond the standard model. Using recent results from the CDF experiment at the Fermilab Tevatron, I show how the search for physics at the TeV scale can take place at the GeV scale and why CDF is, at the moment, unique in it's capability for that search.

Friday 06 February 2004, 16:00: Frank Close, Oxford

"Pentaquarks and tetraquarks: the end of the constituent quark model?"

Friday 16 January 2004, 16:00: Giacomo Polesello, Pavia/CERN

"Discovery physics with the ATLAS detector at the LHC"

We give an overview of the potential of the ATLAS detector for the discovery of new particles at the LHC, based on the expected detector performance and on the proposed analysis strategies. A special emphasis is given to the signatures predicted by supersymmetric models.

Friday 21 November 2003, 16:00: Peter Richardson (CERN/Durham) *TBC*

"Parton Shower Monte Carlos: The State of the Art"

Friday 07 November 2003, 16:00: Ben Allanach (LAPTH)

"R-parity Violating SUSY" (including SUSY primer)

Friday 24 October 2003, 16:00: Rob Edgecock (Rutherford Appleton Laboratory)

"Neutrino Factory: Physics and Prospects"

Friday 10 October 2003, 16:00: Subir Sarkar, Oxford University

The world according to WMAP: Does cosmology now have a Standard Model?

Recent precision observations of anisotropies in the relic 2.7 K radiation by NASA's Wilkinson Microwave Anisotropy Probe are supposed to have determined the values of cosmological parameters to a few per cent, and in particular, to have established the presence of a cosmological constant. We will discuss the assumptions that underlie these results and draw attention to alternative cosmological models which also appear to be consistent with the data.

Friday 06 June 2003, 16:00: Dr. Ruben Saakyan (UCL)

"Neutrinoless Double Beta Decay & NEMO"

Friday 30 May 2003, 16:00: Joao Seco (ICR) — ***POSTPONED UNTIL 20/6/2003***

"Simulations for Intensity Modulated Radiation Treatment (IMRT)"

Friday 23 May 2003, 16:00: Dr. Nigel Smith (RAL) — ***POSTPONED UNTIL 13/6/2003***

"The search for WIMPs in the UK"

Friday 14 March 2003, 16:00: Professor Tim Sumner (Imperial College London)

"The observation of gravitational waves from space using LISA"

Friday 07 March 2003, 16:00: Ankush Mitra (Oxford University)

"LICAS: The Linear Collider Alignment and Survey Project"

Friday 14 February 2003, 16:00: Silvia Miglioranzi (University College London)

"Algorithms Designed to Measure b-quark Production at the ZEUS Experiment at HERA"

Friday 31 January 2003, 16:00: Chris Damerell (Rutherford Appleton Laboratory)

"Feedback from Vertex 2002 Conference"

Monday 20 January 2003, 16:00: Professor Karl van Bibber (Lawrence Livermore National Laboratory)

"A Large-Scale Search for Dark-Matter Axions"

Friday 29 November 2002, 16:00: Stewart Boogert (University College London) — POSTPONED UNTIL 13/12/2002

"Introduction to Linear Collider Physics"

Friday 22 November 2002, 16:00: Dr. Jon Butterworth (University College London)

"HERA physics as a preparation for LHC"

Friday 08 November 2002, 16:00: Professor Tom Ferbel (University of Rochester & Imperial College)

"New Measurement of the Mass of the Top Quark"

Friday 11 October 2002, 16:00: Dr. Lee Thompson (University of Sheffield)

"ANTARES - a neutrino telescope in the Mediterranean" ... or ... "Diving for WIMPs - neutrino astrophysics in the Mediterranean"

Thursday 05 September 2002, 16:00: Professor Paul Singer (Technion - Israel Institute of Technology)

"Rare Charm Decays and the Search for New Physics"

Friday 14 June 2002, 16:00: Greg Landsberg (Brown University)

"Black Hole Production at Future Colliders and Cosmic Rays"

Friday 10 May 2002, 16:00: Steve Biller (Oxford)

"SNO: Latest Results"

Friday 22 March 2002, 16:00: Dr.Cristina Lazzeroni (Cambridge)

"CP Violation Results from NA48"

Friday 15 March 2002, 16:00: Richard Hall-Wilton (UCL)

"Charm Production in DIS at HERA"

Friday 08 March 2002, 16:00: Stefano Moretti (CERN-TH and Durham-IPPP)

"Improving the discovery potential of charged Higgs bosons at Tevatron and the LHC"

Friday 01 February 2002, 16:00: Ed McKigney (Imperial College London)

"MuScat and MICE: Steps toward a Neutrino Factory"

Friday 31 August 2001, 16:00: Ernest Ma (University of Califormia, Riverside)

Verifiable Origin of Neutrino Masses at the TeV Scale and the Muon Anomalous Magnetic Moment.

Tuesday 08 May 2001, 15:00: Uri Karhson (Weizmann/UCL)

Heavy Quark Production at HERA

Friday 16 March 2001, 16:00:

Spreadbury Lecture

Friday 08 December 2000, 16:00: Ivan Reid (UCL)

Muons in Sulphur and Selenium

Friday 24 November 2000, 16:00: Vitaly Kudryavtsev (Sheffield)

Dark Matter searches and neutrino astrophysics.

Friday 17 November 2000, 16:00: David Miller (UCL) (In A19)

Has LEP found the Higgs?

Friday 20 October 2000, 16:00: Angela Wyatt (Manchester).

Rapidity Gaps Between Jets at HERA

Friday 13 October 2000, 16:00: Murray Moinester (Tel Aviv).

Colour Transparency and Exclusive Meson Production at COMPASS

Wednesday 23 August 2000, 14:00: Akos Csilling (UCL)

Photon Structure and More

Don't miss your chance to meet our other OPAL postdoc!

Friday 07 April 2000, 16:00: Dave Waters (Oxford) (TBC)

Measuring the W at the Tevatron

Monday 20 March 2000, 17:15: Alan Watson, University of Leeds — The Elizabeth Spreadbury Lecture

The Quest for the Origin of the Highest Energy Cosmic Rays

Cruciform Lecture Theatre No.1. Tea, squash biscuits etc in South Cloisters at 4.45

Friday 17 March 2000, 16:00: Mark Hindmarsh (Sussex)

The Dynamics of Phase Transitions in the Early Universe

Friday 03 March 2000, 16:00: Pedro Teixeira-Dias (Glasgow)

Higgs searches at LEP

Friday 11 February 2000, 16:00: Paul Newman (Birmingham) (TBC)

Diffractive DIS at HERA.

Friday 21 January 2000, 16:00: Dave Wark (Oxford/Sussex/RAL)

Status of the Sudbury Neutrino Observatory

Friday 10 December 1999, 16:00: Brian Cox, Manchester

Hard Colour-Singlet Exchange at HERA and Tevatron

Note; Rearranged Date!

Friday 26 November 1999, 16:00: Nigel Glover, Durham

Prompt Photon production at LEP and Tevatron

Thursday 25 November 1999, 16:00: Jeff Forshaw, Manchester

Is there a Higgs Boson?

2pm. Note unusual day!

Friday 12 November 1999, 16:00: Roger Jones, Lancaster

Quark and Gluon Jets and Jet Shapes

Friday 05 November 1999, 16:00: Antonio Soares, UCL

Medical Application of a Gamma Camera.

Friday 21 May 1999, 16:00: Prof. Douglas Ross, Southampton.

Electric Dipole Moments of the Electron and Neutron as a Window on New Physics

Tuesday 30 March 1999, 14:00: Dr. Burton Richter, SLAC — Darwin Theatre

The Future of High Energy Physics; a Personal View

Open lecture for the UK particle physics community - Sponsored by PPARC.

Wednesday 24 March 1999, 16:00: Prof. Stanislaw Jadach, CERN

How precise are MC calculations for WW final states?

Friday 19 March 1999, 16:00: Dr. Jason McFall, Bristol

Status of Babar

Friday 26 February 1999, 16:00: Dr. Phil Harris, Sussex

The Search for the Electric Dipole Moment of the Neutron

The discovery of an electric dipole moment of the neutron would have dramatic consequences for particle physics beyond the Standard Model; it may even help us to understand why the universe contains more matter than antimatter. The latest EDM experiment, now running in Grenoble, applies magnetic resonance techniques to stored ultracold neutrons to obtain an extraordinarily high sensitivity, while a newly-developed magnetometer based upon spin-polarised atomic mercury allows unprecedentedly low systematic uncertainties. This talk will cover the motivation behind and the technique of the measurement; the latest results will be presented, together with some ideas for the possible future evolution of the experiment.

Friday 12 February 1999, 16:00: Dr. Neville Harnew, Oxford

LHCB - Detector and Physics Challenge

Friday 05 February 1999, 16:00: Matthew Wing, McGill University/UCL

Semileptonic Decays in ZEUS and Open Beauty at HERA

Friday 29 January 1999, 16:00: Dr. Witek Krasny, Paris/Oxford

Nuclear Options at HERA

The HERA ep collider turned out, rather unexpectedly, to be the best machine for studies of strong interaction physics in the most intriguing domain of transition between soft and hard interactions of real and virtual photons at large and small distances. This unique microscope provide means to look at quarks and gluons in a very broad range of "precisely tunable space-time volumes" and, if nuclear option is realized, using "tunable magnification" of the color forces. What are the perspectives of nuclear program at HERA? Is a curiosity driven research program for eA scattering feasible? I shall try to answer these and other questions in my seminar.

Friday 15 January 1999, 16:00: Dr. John Hassard, ICSTM.

What Can Particle Physics do for DNA Sequencing?

The HEP community in the UK has suffered a large drop in real funding in the last ten years. Paradoxically, our research prospects in HEP may never have been brighter. However, there has been a remarkable drop in applicants to physics - at all levels - partly as a consequence of a perceived lack of future for the subject as a discipline in its own right. Few would dispute the long-term importance of pure research at a cultural and societal level; many consider an emphasis on short-term spin-offs to be irrelevant or even counterproductive. I will illustrate the short-term utility of physics in general and HEP in particular by discussing our biotechnology and biomedicine programmes and making the connection to pure research. My central thesis is that if we take care of the short term, the long term takes care of itself. The key is in making the connection.

Monday 14 December 1998, 16:00: Carsten Hensel (Hamburg University)

Beam induced Background at a Detector at a 500 GeV Electron-Positron Linear Collider

Wednesday 25 November 1998, 16:00: Aude Gehrmann-De Ridder (Karlsruhe University)

Photon structure at LEP and Linear Collider

Wednesday 07 October 1998, 13:00:

IoP Half day meeting on future physics.

Wednesday 30 September 1998, 16:00: Jason Ward (Glasgow)

W Physics Results from ALEPH

Tuesday 15 September 1998, 16:00: Thomas Hadig (Aachen)

Measuring the Gluon Density in the Proton at H1

Monday 20 July 1998, 16:00: Greg Landsberg (Brown)

Search for Exotics at D0

Wednesday 03 June 1998, 16:00: David Miller (RAL) (no relation)

Heavy Quarks from Gluon Splitting at LEP

Wednesday 20 May 1998, 16:00: Marco Stratmann (Durham)

Physics at a Polarised HERA

Wednesday 13 May 1998, 16:00: Paul Dervan (UCL)

Silicon Vertex Detectors

Wednesday 06 May 1998, 16:00: Ben Allanach (RAL)

Increased Predictivity in Supersymmetry

Wednesday 29 April 1998, 16:00: Chris Llewellyn-Smith (CERN)

Colloquium - The LHC Program

Wednesday 22 April 1998, 16:00: David Miller (UCL)

Lepton collider prospects

Friday 03 April 1998, 16:00: Rajendran Raja (FNAL)

Top quark Physics results from the Tevatron

Wednesday 18 March 1998, 16:00: Martin McDermott (Manchester)

Diffractive Heavy Quarkonium production

Monday 16 March 1998, 16:00: Malcolm Longair (Cambridge)

The Enigma of the Cosmological Constant, The Elizabeth Spreadbury Lecture

Wednesday 11 March 1998, 16:00:

IoP HEPP Group Half Day at UCL on Neutrino Physics

Wednesday 04 March 1998, 16:00: Michael Kramer (RAL)

Current status of Quarkonia Physics

Wednesday 18 February 1998, 16:00: Paul Dervan (UCL)

The SLD vertex detector upgrade.

Monday 16 February 1998, 16:00: Martin Rees (at STS)

Our Universe and Others

Wednesday 28 January 1998, 16:00: Simon George (RHBNC)

The ATLAS SCT Trigger

Wednesday 21 January 1998, 16:00: Prof. H. M. Chan (RAL)

Are post-GZK air showers due to strongly interacting neutrinos?

Joint with Astronomy group, in the Massey Theatre

Wednesday 14 January 1998, 16:00: Prof. D. H. Davis

Hypernuclei

Wednesday 10 December 1997, 16:00: Paul Dauncey (RAL)

Measuring the CKM angle gamma at BaBar

Tuesday 09 December 1997, 16:00: Neville Harnew (Oxford)

Observation of ring patterns with a pixellated single-photon detector

The proposed LHC-B experiment at CERN will use a novel photon detection device called the hybrid Photon Detector (HPD) to recognise rings of Cherenkov light produced by high energy particles in matter. Electrons from a photocathode surface in the HPD are accelerated and detected in a silicon pad detctor. NB. This is not a Bloomsbury seminar, but one of a series organised but CAIS/Sira UCL postgrad centre. It will be at 3pm in the M.Res seminar room, 66-72 Gower St.

Wednesday 03 December 1997, 16:00: Phil Burrows (SLAC)

Testing the Standard Model using Polarised Electrons, a Micro-vertex Detector and Particle Identification: the SLD Experiment at SLAC

Wednesday 19 November 1997, 16:00: Prof. Ian Percival, QMW

Quantum technology and quantum foundations (Joint with Molecular and Atomic Physics, will be held in A1)

Wednesday 12 November 1997, 16:00: Prof. Basil Hiley, Birkbeck

Alternative Quantum Mechanical Interpretations: Do they really help? (Joint with Molecular and Atomic Physics, will be held in A1)

Wednesday 05 November 1997, 16:00: Stan Wojcicki (Stanford U.)

Brookhaven Rare Kaon Decay Experiment

Wednesday 22 October 1997, 16:00: Herbi Dreiner (RAL)

R-parity violation

Wednesday 15 October 1997, 16:00: Vakhtang Kartvelishvili (Manchester)

SVD Approach to Data Unfolding

Distributions measured in high energy physics experiments are usually distorted and/or transformed by various detector effects. A regularization method for unfolding these distributions is re-formulated in terms of the Singular Value Decomposition (SVD) of the response matrix. A relatively simple, yet quite efficient unfolding procedure is explained in detail. The concise linear algorithm results in a straightforward implementation with full error propagation, including the complete covariance matrix and its inverse. Several improvements upon widely used procedures are proposed, and recommendations are given how to simplify the task by the proper choice of the matrix. Ways of determining the optimal value of the regularization parameter are suggested and discussed, and several examples illustrating the use of the method are presented.

Thursday 02 October 1997, 16:00: Mike Seymour (RAL) THURSDAY!!

The Internal Structure of QCD Jets

Wednesday 24 September 1997, 16:00: Jan Lauber (UCL)

Summary of Jerusalem conference (EPS97)

Wednesday 04 June 1997, 16:00: Mark Hayes (Bristol University)

Hard diffractive scattering in photo-production at HERA

Wednesday 28 May 1997, 16:00: Tony Rooke (University College London)

Summary of the Photon 97 conference

Wednesday 21 May 1997, 16:00: Peter F. Smith (RAL)

Measurement of the neutrino mass from supernova

Wednesday 14 May 1997, 16:00: Allan Skillman (University College London)

Determination of the Trilinear Gauge Couplings in WW events at LEP II at a center of mass energy of 172 GeV

Wednesday 26 March 1997, 16:00: John Thompson (RAL)

ALEPH LEP 2 Results

Wednesday 19 March 1997, 16:00: Claude Bourrely (Birkbeck)(UCL)

Theory of Deep inelastic scattering

Wednesday 12 March 1997, 16:00: Lynne Orr (University of Rochester)

Gluon Radiation in Top Quark Production and Decay

The strong force causes quarks to radiate gluons with a large probability. Because these gluons appear in experiments as jets of hadrons which are typically indistinguishable from jets due to quarks, making sense of these experiments requires understanding gluon radiation. This is particularly important for top physics because uncertainties in future top measurements will be dominated by systematic effects associated with gluon radiation. Gluons can be radiated during both top production and decay; both processes must be taken into account. In this seminar I discuss gluon radiation in top quark production and decay at present and future colliders (both hadron and electron-positron colliders), and some implications of the results.

Tuesday 25 February 1997, 16:00: Jon Butterworth (UCL)

HERA and the Leptoquark — Is the Standard Model dead ?

Results presented last week by the H1 and ZEUS experiments at DESY, Hamburg (and submitted to journals this week) have caused something of a stir. Interest focusses on comparisons between positron-proton scattering data and the predictions of the 'Standard Model' of particle physics. Anomalies are seen in the data when the four-momentum transfer is high (Q^2 > 15000 GeV^2) and the momentum fraction of the struck quark in the proton is around x = 0.5. After a simple outline of the Standard Model and of the experiments is given, the significance and implications of these anomalies will be examined.

Wednesday 19 February 1997, 16:00: Boris Ruskov (Oxford)

From QED to QCD — from similarities to differences

The purpose of this lecture is to give an elementary introduction to basic ideas of the non-perturbative QCD. The universal gauge-theory description of QCD and QED will be given. Considering both models in parallel, we will explain the reason for similarities between them in the weak-coupling regime and crucial differences in the strong-coupling (non-perturbative) region. We will discuss some ideas on how these properties can be observed.

Wednesday 12 February 1997, 16:00: No Seminar

OPAL UK Meeting

Wednesday 05 February 1997, 16:00: Roger Barlow (Manchester)

Why physics lectures

Wednesday 29 January 1997, 16:00: Jon Flynn (Southampton)

Some recent results from Lattice QCD

I review some recent lattice QCD results for quantities of phenomenological interest. After a brief consumer guide I will survey recent results for some or all of: B-meson decay constant and mixing parameter, K-meson mixing parameter, strong coupling constant, light quark masses and the lightest scalar glueball.

Wednesday 22 January 1997, 16:00: Hugh Gallagher (Oxford)

New Results on Atmospheric Neutrino Oscillations from Soudan 2

Wednesday 27 November 1996, 16:00: Dr C. Damerell (RAL)

The international e+e- linear collider programme: physics prospects and recent design developements

The future e+e- linear collider was one of the options studied in detail at the recent Snowmass Workshop 'New Directions for High Energy Physics'. This talk (which includes material presented in the closing parallel session) summarises recent progress on the accelerator and detector design, and contrasts the physics prospects with other options discussed during the workshop.

Wednesday 20 November 1996, 16:00: Prof. I Percival (QMW)

Quantum mechanics, cat-fleas and gravit

By analogy with the use of Brownian motion to detect flucuations on the atomic scale, it is shown that modern matter interferometry experiments might detect fluctuations of space-time on a Planck scale, despite the small values of the Planck length and time.

Wednesday 13 November 1996, 16:00: Dr B. Webber (Cavendish Laboratory)

"Hadronisation" corrections to QCD observables

Predictions in perturbative QCD refer to final states consisting of quarks and gluons, rather than the hadrons actually observed in experiments. It has therefore been customary to apply `hadronization'' corrections, based on Monte Carlo models, to the theory before comparing with experiment. Although this procedure seems to fit the data quite well, the corrections applied have not been well justified theoretically. Empirically, they behave like inverse powers of a large momentum scale of the process, for example the centre-of-mass energy in e+e- annihilation or the quark mass in heavy quark processes. Recent theoretical work has suggested that such power-suppressed corrections can arise from divergences of the perturbation series at high orders, which are called `renormalons''. This talk will explore the insights into hadronization corrections that can be obtained from the renormalon approach.

Wednesday 06 November 1996, 16:00: Dr C. Sutton (Oxford)

Communicating science

Wednesday 30 October 1996, 16:00: Dr O Teryaev (Dubna and Birkbeck)

QCD single spin asymmetries in the RHIC and HERA-N programmes

Wednesday 23 October 1996, 16:00: Dr J. McGovern (Manchester)

Chiral symmetry in nuclei

Partial restoration in nuclear matter of the chiral symmetry of QCD is discussed together with some of its possible signals. Estimates of corrections to the leading, linear dependence of the quark condensate are found to be small, implying a significant reduction of that condensate in matter. The importance of the pion cloud for the scalar quark density of a single nucleon indicates a close connection between chiral symmetry restoration and the attractive two-pion exchange interaction between nucleons. This force is sufficiently long-ranged that nucleons in nuclear matter will feel a significant degree of symmetry restoration despite the strong correlations between them. Expected consequences of this include reductions in hadron masses and decay constants. Various signals of these effects are discussed, in particular the enhancement of the axial charge of a nucleon in matter.

Wednesday 16 October 1996, 16:00: Prof E. Leader (Birkbeck)

Report on the 12th Int. Symp. on High Energy Spin Physics, Amsterdam

Wednesday 09 October 1996, 16:00: Prof D. Miller (UCL) and Dr J. Lauber (UCL)

Report on the INternational Conference on High Energy Physics, Warsaw

Wednesday 05 June 1996, 16:00: Dr Dhiman Chakraborty (State University of New York at Stony Brook)

The current status of top physics at the Tevatron

The Tevatron accelerator at Fermilab has recently concluded a run in the collider mode before switching to the fixed-target mode of operation for the next 3 years. Each of the two collider experiments, CDF and D0, has collected over 100 pb**-1 worth of data which is about twice what the last batch of publications were based on. The first results from this full data sample have just started to come out. In the arena of top physics, both experiments have revised their calculations of production cross-section and the mass of top quarks with reduced statistical and systematic errors. These as well as some new results from more difficult final states and a breif outline of future prospects will be presented.

Wednesday 29 May 1996, 16:00: Dr Mike Charlton (University College)

AntiHydrogen

Antihydrogen was recently observed at high energies at CERN. We briefly review this experiment, but suggest that the primary motivations for studying this object, which include CPT and WEP tests, can only be addressed by its controlled production at very low energies. Techniques which will allow this are described, including the capture and cooling of antiprotons to temperatures below 20K and the accumulation of dense positron plasmas.

Wednesday 22 May 1996, 16:00: Nick Allen (Brunel University)

Electroweak Measurements at SLD

Wednesday 15 May 1996, 16:00:Dr George Lafferty (Manchester)

Inclusive particle production in hadronic Z decay

An overview will be given of the physics results from the study of inclusive particle production in multihadronic Z decays at LEP, the primary aim of which is to reach an understanding of the non-perturbative hadronisation process in QCD. Topics covered will include: aspects of quark and gluon fragmentation; local parton-hadron duality; QCD-based models of parton hadronisation; two-particle correlations; and spin effects in fragmetation.

Wednesday 08 May 1996, 16:00: Barry Macevoy (Imperial College)

Defect kinetics in silicon detector material

A numerical kinetics model has been used to investigate the evolution of complex defects in high resistivity silicon detector material during fast neutron irradiation to levels expected at the CERN LHC. The complex V_2O is identified as a candidate for a deep-level acceptor state which gives rise to experimentally observed changes in the effective doping concentration. The importance of the initial oxygen impurity concentration in determining the radiation tolerance of the detectors is demonstrated. The characteristics of devices heavily irradiated with Colbalt 60 photons are modelled satisfactorily by using a semiconductor simulation in conjunction with the kinetics model. It is postulated that inter-defect transitions between divacancy states in the terminal damage clusters are responsible for apparent discrepancies in the modelling of data from neutron-irradiated devices. This mechanism (if correct) may have important consequences for te prospects of "defect-engineering" a radiation hard device.

Tuesday 12 December 1995, 16:00: Dr Greg Heath (Bristol)

Hunting the Higgs Boson - In a Haystack

Particle physics experiments produce enormous raw data rates. Millions of events per second must be filtered on-line to find a few dozen of interest. Filtering processors will be described and the strategies used on them, for current experiments and for the future Large Hadron Collider at CERN.

Wednesday 29 November 1995, 16:00: Dr Jeff Forshaw (Manchester)

Report on the Beijing Lepton-Photon Conference

Wednesday 22 November 1995, 16:00: Dr Roger Phillips (DRAL)

Speculations about the KARMEN Anomaly

The KARMEN experiment, studying neutrinos from the pi+ decay chain, has found an anomaly in the time-dependence that suggests a new unstable particle x with m(x)=33.9 MeV, produced via pi -> mu+x . Could this be a new neutrino or what? Pros, cons, ifs and buts will be reviewed.

Wednesday 15 November 1995, 16:00: Dr Subir Sarkar (Oxford)

"No-crisis" for Big Bang Nucleosynthesis

The synthesis of the light elements at the end of the `first three minutes' provides the most detailed probe of physical conditions in the early universe and has proved very useful in constraining new physics, viz. the existence of new particles and forces. Recently it was claimed that the observationally inferred abundances of deuterium, helium and lithium are in fact inconsistent with even the Standard Model, thus undermining this programme. I will review the situation and argue that there is no such crisis.

Wednesday 08 November 1995, 16:00: Prof John Edgington (QMW)

Neutrino Oscillations - Weighing the Evidence

Do neutrinos possess mass? The Standard Model says no, without giving a reason. So far there is no direct and sustainable experimental evidence for mass, despite occasional hints to the contrary. To some, non-zero mass is more "natural" and cosmologists seeking missing mass have supported this theological view with enthusiasm. Massive neutrinos will have wave functions which are combinations of separate flavour eigenstates; thus production of neutrinos of one flavour and their detection as another flavour is evidence for non-zero mass. Experimental searches for neutrino oscillations will be reviewed, concentrating on the KARMEN experiment at Rutherford Appleton Laboratory and comparing it with the LSND experiment at Los Alamos National Laboratory. Some problems of drawing conclusions will be discussed, including the relevance of a Bayesian approach to data handling.

Wednesday 01 November 1995, 16:00: Dr. D. B. Stamenov (INR, Bulgarian Academy of Sciences)

Constraints on "Fixed Point" QCD from the CCFR data on DIS

Wednesday 25 October 1995, 16:00: Dr Robert Thorne (DRAL)

Report on the European Physical Society HEP Meeting, Brussels

I will attempt to summarize some of the most important and interesting developments reported at the Meeting. This is clearly a personal choice, but the topics to be discussed include: developments in perturbative QCD, particularly small x physics, high pT jets, and higher twist corrections; particle-astrophysics and the solar neutrino problem; precision measurements (particularly R_b and R_c) and calculations in the standard model, and implications for new physics; and duality in supersymmetric theories.

Wednesday 11 October 1995, 16:00: Prof John Dainton (Liverpool)

The Partonic Structure of Diffraction

Recent new measurements of the deep-inelastic scattering of electrons on protons have revealed a new layer in our understanding of the structure of the proton. At the highest possible interaction energies, which are available only at the HERA ep collider in DESY in Hamburg, new measurements have revealed a contribution which is due to the way protons interact with other hadrons. The first measurements of the short distance structure of this contribution reveal that it is partonic, and furthermore that it may be understood in terms of Quantum Chromodynamics (QCD). For the first time, deep-inelastic lepton scattering experiments are able to probe one of the oldest conundrums in physics, namely the way nucleons interact with other nucleons (often generically referred to as diffraction), and to provide measurements which elucidate an understanding in terms of QCD. The new results which lead to these conclusions are presented and discussed.

Wednesday 14 June 1995, 16:00: Jason Ward

Measurement of the Photon Structure Function at OPAL

An introduction to how photon structure is studied at an electron-positron collider is given, with motivation for such a study. The new contributions that LEP can make to the measurement of the photon structure function are discussed and the OPAL measurements are presented. These measurements are compared with theory. The photon structure function measurements that we expect from future LEP-II running are also discussed.

Wednesday 31 May 1995, 16:00: Prof. Roger Cashmore (Oxford)

The Top Quark - Discovery and Implications

The evidence for the recent discovery of the top quark at Fermilab will be reviewed and the implications for other areas of particle physics discussed. Further progress in top quark physics will be made with upgrades to the Tevatron and the construction of the LHC while a high energy linear e+/e- collider offers intriguing possibilities. These aspects will be developed and put in perspective.

Wednesday 24 May 1995, 16:00: Dr Alexei Yung (St. Petersburg / Swansea)

Why Topological Models are Relevant to Physics

An elementary introduction to what is topological field theory is given. The problem how topological models could serve physics is discussed. In particular, the idea that the physical theory could correspond to the broken phase of the topological theory is explained. The example of such breakdown phenomenon in the two dimensional topological sigma model is presented.

Wednesday 17 May 1995, 16:00: Dr Paul Harrison (Queen Mary)

A Solution to the Solar and Atmospheric Neutrino Problem

Wednesday 10 May 1995, 16:00: Dr Brian Foster (Bristol)

The BaBar Experiment

I will motivate the study of CP violation in the B system by the need to understand the baryone asymmetry of the Universe. I will discuss the possible mechanisms of CP violation and various formalisms in which to understand and express them. I will discuss the requirements for an experiment to study CP violation in the B system and then show how these are being realised in the design of the BaBar experiment at PEP-II

Wednesday 03 May 1995, 16:00: Dr Alfred Goldhaber (Stony Brook / Cambridge)

An Open Universe from Inflation

A model is described in which inflation occurs, with many of the features customarily associated with inflation, but the universe today may still exhibit appreciable negative curvature, e.g. Omega = 0.2. This is achieved without extremely fine tuning if the inflation proceeds in two stages. The first, or old inflation, stage, is one with a local minimum in the vacuum energy associated with the inflaton field, and implies a de Sitter universe. At some point a bubble forms through a a quantum transition, with new or slow-roll inflation proceeding inside. This bubble evolves into our visible universe, and the slow roll must involve a change in the magnitude of the inflaton field of the same order as the Planck scale. Tuning in the initial value (delta Phi)/Phi around 0.01 to 0.1 would be sufficient to give agreement with current observations. The model has been presented in a recent paper by M. Bucher, A.S. Goldhaber, and N. Turok, and further developed in work by Bucher and Turok.

Wednesday 15 March 1995, 16:00: Dr Apostolos Pilaftsis (DRAL)

How Left-Right Asymmetry, Tau Polarization and Lepton Universality Constrain Unified Theories at the Z Peak

We suggest the use of a universality-breaking observable based on lepton asymmetries at the Z peak, which can efficiently constrain the parameter space of unified theories. The new observable is complementary to the common lepton-universality quantity relying on partial width differences and depends critically on the chirality of a possible non-universal Z-boson coupling to like- flavour leptons. The LEP potential of probing universality violation is discussed in representative low-energy extensions of the Standard Model (SM) that may be motivated by supersymmetric grand unified theories, such as the SM with left-handed and/or right-handed neutral isosinglets, the left-right symmetric model, and the minimal supersymmetric SM.

Wednesday 08 March 1995, 16:00: Dr Mike Green (RHBNC)

The Search for the Higgs Boson at LEP I and LEP II

One of the most important outstanding issues for the standard model is the origin of mass. The most popular mechanism for generating mass requires the existence of one or more Higgs bosons with a mass below about 1 TeV. Prior to the operation of LEP there was very little opportunity to search for these and only a very small mass range close to zero was excluded. In the first few years of LEP running the whole mass range below 60 GeV has been excluded for the minimum standard model Higgs. At LEP II the sensitivity will be extended up to at least 80 GeV and hopefully higher. Direct searches above this mass will depend on LHC. However virtual effects in electroweak processes and a direct measurement of the top mass can help pin the Higgs down to a restricted mass region

Wednesday 22 February 1995, 16:00: Dr Werner Vogelsang (DRAL)

Prompt Photon Production at Hera

We first review the status of prompt photon production in hadronic collisions, focussing in particular on the situation at high-energy ppbar colliders, where we show how the longstanding discrepancy between data and theory at small pt/S is removed by using steep small-x parton distributrions and also by taking into account the fragmentation contribution in next-to-leading order. Then we turn to prompt photon production at HERA and study its sensitivity to the parton, in particular the gluon, content of the photon in the framework of a complete next-to-leading order calculation. Special attention is paid to the issue of isolation constraints imposed on the cross section by experiment.

Wednesday 15 February 1995, 16:00: Dr Tim Greenshaw (Liverpool)

Recent Results from H1

Wednesday 25th January 1995, 16:00: Prof David Miller

The Next Collider(s) after LHC

The LHC must come first, but then what? There is important physics which other colliders can do but which LHC will find difficult or impossible. Technical and physics questions will be reviewed.

Wednesday 18 January 1995, 16:00: Dr Neville Harnew (Oxford)

Exotic Physics Searches at Hera

During the 1993 running period of the HERA e-p collider, the ZEUS and H1 detectors each recorded approximately 550 inverse picobarns of integrated luminosity. I report on searches from both experiments for particles beyond the Standard Model, in which HERA is able to explore an entirely new kinematic range. Topics considered include the hunt for direct, indirect and flavour-changing leptoquarks, predicted in extensions to the Standard Model. I will also review the status of the search for excited electrons, neutrinos and quarks, all of which are predicted in composite models. Finally, I will discuss the prospects for the discovery of SUSY at HERA, both in the R-parity conserving and R-parity violating production and decay modes.

Wednesday 07 December 1994, 16:00: Dr Allan Skillman

Inclusive Strange Vector and Tensor Meson Production in Hadronic Z Decays

Measurements have been made in the OPAL experiment at LEP of the inclusive production of strange vector phi(1020) and K*(892) mesons, and the neutral tensor meson K*(1430). The measurements for the vector states update previously published results based on lower statistics, while the K*(1430) rate represents the first measurement of a strange tensor state in Z0 decay. Both the overall production rates, and normalised differential cross sections for the vector states, have been compared to JETSET and HERWIG predictions. The peak positions in the xi = ln(1/xp) distributions have been measured and found to be consistent with measurements of other hadron states.

Wednesday 30 November 1994, 16:00: Dr Jeff Forshaw (DRAL)

Diffractive Vector Meson Production at Large Momentum Transfer

HERA is able to observe diffractive production of vector mesons. Their observation at large momentum transfer will provide important information regarding the nature of the pomeron in QCD

Wednesday 23 November 1994, 16:00: Dr Nick Brook (Glasgow)

The Hadronic Final State in Deep Inelastic Scattering at Zeus

The general characteristics of the hadronic final state in deep inelastic, neutral current electron-proton interactions at ZEUS are investigated for Q2 > 10 GeV2. The general properties of events with a large rapidity gap are investigated and compared to events without a rapidity gap. The kinematic properties of the jets in 2-jet events are measured and compared to NLO calculations. Fragmentation effects are investigated in the current fragmentation region. The data are used to study QCD coherence effects in DIS and to compare with corresponding e+e- data in order to test the universality of quark fragmentation.

Wednesday 02 November 1994, 16:00: Prof Elliot Leader

The Present Status of Polarised Deep Inelastic Scattering

The unexpected results of the EMC experiment in 1987, using a longitudinally polarised lepton beam on a longitudinally polarised hydrogen target, with its suggestion of a "spin crisis in the parton model" catalysed an enormous amount of theoretical and experimental work. What that was regarded as a trivial extension of the unpolarised case is now seen to be a rich field of its own, full of subtleties. Several new experiments reported results during 1993/4. The first data on neutrons appeared and led initially to claims that the fundamental Bjorken sum rule was violated. The seminar will cover both the theory and phenomenology .

Friday 28 October 1994, 16:00: Dr Lev Chekhtman (CERN/Novosibirsk)

Microstrip Gas Chambers - Possible Applications for X-ray Detection

Existing low-dose digital X-ray systems have much worse spatial resolution than photographic film/screen techniques. Microstrip gas chambers offer resolutions of around 100 microns and may have larger area than solid-state strip or CCD detectors.

Wednesday 26 October 1994, 16:00: Dr Robert Bingham (DRAL)

Particle Acceleration in Plasmas using High Powered Lasers

The generation of relativistic plasma waves in low density plasmas is important in the quest for producing ultra-high acceleration gradients for accelerators. At present two methods are being pursued vigorously to achieve ultra-high acceleration gradients. The first is the beat wave mechanism which uses conventional long pulses (>100 ps) modest intensity lasers (I ~ 10E14 Watts/cm2 - 10E16 Watts/cm2) and the second uses the new breed of compact high brightness lasers (< 1 ps) and intensities > 10E18 Watts/cm2. With the development of these compact short pulse high brightness lasers new areas of study for laser matter interactions is opening up. In the ultra-high intensity regime laser plasma interactions are highly nonlinear and relativistic leading to new phenomenon such as plasma wakefield excitation for particle acceleration, relativistic self-focusing, remote guiding of laser beams, harmonic generation and photon acceleration.

Friday 21 October 1994, 16:00: Dr John Hassard (IC)

Diamond Detectors: Towards the Frontiers of Technology

Diamond films are strictly insulators, but they are excellent photoconductors (and conductors of heat). As detectors for ionising particles they may be especially interesting for high-radiation environments in nuclear medicine and at future particle colliders.

Wednesday 12 October 1994, 16:00: Prof Tegid Jones, Prof David Miller, Dr Mark Thomson

Glasgow Conference Review

Tegid, David and Mark will be telling us about the highlights of that sunny week in July, north of the border.