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HEP Seminars

01 Jun 2020

UCL HEP Seminars 2009

11/12/2009 : 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.

04/12/2009 : 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]

06/11/2009 : 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!

30/10/2009 : 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.

16/10/2009 : 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.

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25/09/2009 : 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.

07/08/2009 : 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.

05/06/2009 : 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.

15/05/2009 : Mark Dorman (UCL) -- Physics E7 at 4pm

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.

08/05/2009 : 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.

01/05/2009 -- E7 at 3:15pm : Michela Massimi (UCL)

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

24/04/2009 : Filipe Abdalla (UCL)

Neutrino Mass contstraints from cosmology

17/04/2009 : Jim Hinton (Leeds)

Gamma Ray Astronomy

27/03/2009 : Are Raklev (University of Cambridge)

Gravitino Dark Matter

20/03/2009 : Phil Harris (University of Sussex)

Testing Time Reversal

13/03/2009 : 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.

27/02/2009 -- 3pm Gustave Tuck Lecture Theatre

Origins Launch

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

25/02/2009 -- Department Colloquium -- Wednesday -- Harrie Massey : Tom McLeish

13/02/2009 -- 1:30pm Maths 706

Origins -- Mathematical Foundations

23/01/2009 : 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.