Dennis Patrick Wendland
(Institut fuer Physik)
04/06/2012, 16:00
Heavy Flavour Physics
Poster
Top-quark precision measurements are of central importance to the LHC physics program. The top-quark is the heaviest known fundamental particle with unique properties within the Standard Model (SM). Its large couplings to the Higgs boson, and being the only quark that decays before hadronisation make it sensitive to new physics beyond the SM. Among the places to look for deviations from the...
Warren Andrews
(Univ. of California San Diego (US))
04/06/2012, 16:00
Standard Model & Beyond
Poster
We present a search for new physics in the final state of a leptonically decaying Z boson and missing transverse energy (MET) utilizing the full 2011 dataset collected by the CMS detector. Two complementary search regions are investigated. The first requires a leptonic Z and two or more jets, and searches in the high MET tail. The second applies additional requirements to increase sensitivity...
Michele Petteni
(SFU Simon Fraser University (CA))
04/06/2012, 16:00
Heavy Flavour Physics
Poster
A search for top quark pair ttbar resonances in final states where both W bosons from the top quark decay into either an electron and electron-neutrino or a muon and muon-neutrino (dilepton final state) has been performed. The data were recorded by the ATLAS experiment at the CERN Large Hadron Collider. The search uses a data sample corresponding to an integrated luminosity of 2.05 fb-1, which...
Mr
Alberto Tonero
(SISSA)
04/06/2012, 16:00
Standard Model & Beyond
Poster
In absence of a fundamental Higgs boson, the dynamics of the SU(2)xU(1) symmetry breaking can be described by coupling gauge bosons and fermions to a nonlinear sigma model. Normally this is regarded only as an approximate description valid up to some cutoff energy scale. However, if there is a UV fixed point, this model in which the Nambu-Goldstone bosons can be thought of as fundamental...
Doug Schouten
(TRIUMF (CA))
04/06/2012, 16:00
Higgs Boson
Poster
Gordon Watts
(University of Washington (US))
04/06/2012, 16:00
Heavy Flavour Physics
Poster
The ATLAS collaboration calibrates its b-tagging algorithms using a number of data-driven methods. The b-tagging algorithms, used to separate b-quark jets from light-quark jets, are widely used in top, Higgs, and Exotics analyses in ATLAS. The algorithm’s performance is measured for light-quark jets, charm jets, and bottom jets. In some cases multiple methods can be used to measure the...
Vikas Bansal
(University of Victoria (CA))
04/06/2012, 16:00
Standard Model & Beyond
Poster
A wide range of new physics phenomena can produce modifications to the dilepton mass spectra predicted by the standard model (SM) such as quark/lepton compositeness, extra dimensions, and new gauge bosons. The predicted form of these deviations is often either a resonance or an excess in the number of events in the spectra at high mass. This work presents a search for contact interactions in...
Sean Benson
(University of Edinburgh (GB))
04/06/2012, 16:00
Heavy Flavour Physics
Poster
An untagged, time-integrated analysis of the $B_s \to \phi \phi$ decay has been performed with 1 fb$^{-1}$ of pp collision data at centre-of-mass energy $\sqrt{s} = 7$ TeV taken using the LHCb detector. Optimised selections have yielded 801 $B_s \to \phi \phi$ events at high signal to background ratio. This has allowed for measurements of polarisation amplitudes ($|A_0|^2$, $|A_\perp|^2$,...
Jennifer Lynn Godfrey
(SFU Simon Fraser University (CA))
04/06/2012, 16:00
Heavy Flavour Physics
Poster
We present a measurement of the top-quark pair production cross-section in the tau+lepton channel in proton-proton collisions at 7 TeV with the ATLAS detector at the Large Hadron Collider. Events with an isolated electron or muon and a tau lepton decaying hadronically are used. In addition, a large missing transverse momentum and two or more energetic jets are required. At least one of the...
Mr
Wolf Behrenhoff
(Deutsches Elektronen-Synchrotron (DE))
04/06/2012, 16:00
Standard Model & Beyond
Poster
We present measurements of various differential cross sections in top pair production in proton-proton collisions at the LHC at a centre-of-mass energy of 7 TeV. The data are collected by the CMS experiment during the year 2011. Cross sections are measured differentially as a function of various variables, including the transverse momentum and rapidity of the (anti)top quark as well as the...
Andrea Ferretto Parodi
(Sezione di Genova)
04/06/2012, 16:00
Standard Model & Beyond
Poster
The identification of jets originating from b-quarks (b-tagging)is a crucial tool for the LHC physics program, both for precision measurements and in searches for new particles. One important ingredient when using b-tagging in physics analyses is the determination of the probability to mistakenly b-tag a jet originating from a c-quark (c-tag efficiency). The optimal sample for the measurement...
Christian Andreas Jung
(Technische Universitaet Dortmund (DE))
04/06/2012, 16:00
Standard Model & Beyond
Poster
The identification of jets originating from b-quarks, referred to as b-tagging, is an important part of the LHC physics program. In precision easurements in the top quark sector as well as in the search for the Higgs boson and new phenomena, the suppression of background processes containing predominantly light-flavour jets using b-tagging is of great use. In order for b-tagging to be used in...
Dominik Duda
(Fachbereich C / Physik)
04/06/2012, 16:00
Standard Model & Beyond
Poster
Many physics analyses with the ATLAS detector expect to have jet originating from b-quarks in the final state. Algorithms that allow to identify such jets are thus of great importance and it is crucial to understand their performance with data-driven measurements of efficiencies and fake rates. Since the top quark almost exclusively decays to a W boson and a b-quark, a sample of top anti-top...
Daniel Johnson
(University of Oxford (GB))
04/06/2012, 16:00
Heavy Flavour Physics
Poster
An analysis of $B^\pm \to DK^\pm$ and $B^\pm \to D\pi^\pm$ decays is presented where the D meson is reconstructed in the two-body final states: $K^\pm \pi^\mp$, $K^+K^−$ and $\pi^+\pi^-$. Using 1.0 fb$^{−1}$ of LHCb data, measurements of several observables are made including the first observation of the suppressed mode $B^\pm \to [\pi^\pm K^\mp] DK^\pm$. CP violation in $B^\pm \to DK^\pm$...
Darius Jurciukonis
(Vilnius University (LT))
04/06/2012, 16:00
Standard Model & Beyond
Poster
The smallness of the neutrino masses can be well understood within the seesaw mechanism (type I). After spontaneous symmetry breaking of the Standard Model gauge group one obtains a $(n_L+n_R)\times(n_L+n_R)$ Majorana mass matrix $M_\nu$ for neutrinos. The mixing between the $n_R$ right-handed neutrino singlets and the neutral parts of the $n_L$ lepton doublets gives masses for the neutrinos...
Daniele Zanzi
(Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut) (D)
04/06/2012, 16:00
Standard Model & Beyond
Poster
Physics involving tau lepton signatures form an integral part of the ATLAS physics program, and are becoming more prevalent, given the large amounts of data accumulated in 2011 and 2012 LHC running. This talk reviews the increased sensitivity of searches for a Standard Model Higgs boson in the low mass region, as well as searches for neutral and charged supersymmetric Higgs bosons, decaying to...
Mr
Alberto Tonero
(SISSA/INFN)
04/06/2012, 16:00
Standard Model & Beyond
Poster
Quark contact interactions are an important signal of new physics. A model in which the presence of a symmetry protects these new interactions from giving large corrections in flavor changing processes at low energies is introduced. It provides the basic set of operators which must be considered to contribute to the high-energy processes. The discussion of their experimental signature at the...
Cosme Adrover Pacheco
(CPPM - Universite d'Aix - Marseille II (FR))
04/06/2012, 16:00
Heavy Flavour Physics
Poster
A search for $B^0_s \to \mu^+\mu^−$ and $B^0_s \to \mu^+\mu^−$$ decays is performed using 1.0 fb$^{−1}$ of pp collision data collected at $\sqrt{s}=7$ TeV with the LHCb experiment at the Large Hadron Collider. For both decays the number of observed events is consistent with expectation from background and Standard Model signal predictions. Upper limits on the branching fractions are determined...
Mr
Rocky So
(University of British Columbia)
04/06/2012, 16:00
Higgs Boson
Poster
Babar collided electrons and positrons at a centre of mass energy of ~10GeV at the Stanford Linear Accelerator Center. A light CP-odd Higgs boson is expected in extensions to the Standard Model such as Next to Minimal Supersymmetry. The Babar Collaboration searched for a light Higgs boson (A0) produced in radiative decays of an Υ meson (Υ → γA0). We saw no evidence of the A0 decaying into...
Anna Katharina Kopp
(Albert-Ludwigs-Universitaet Freiburg (DE))
04/06/2012, 16:00
Higgs Boson
Poster
Matthew Ryan Relich
(Department of Physics-University of California Irvine)
04/06/2012, 16:00
Standard Model & Beyond
Poster
The discovery of neutrino oscillations established that neutrinos have non-zero mass and provided clear evidence for physics beyond the Standard Model. One possible explanation for the mass of light neutrinos is provided by theoretical models based on ideas of Grand Unification. Such models usually introduce additional neutrino fields, which manifest themselves as the new heavy particles that...
Seth Cooper
(School of Physics and Astronomy)
04/06/2012, 16:00
Standard Model & Beyond
Poster
Several models of new physics, including split supersymmetry, predict the existence of a heavy particle, which is long-lived on the timescales of the bunch spacing of the Large Hadron Collider (LHC). Such a particle would be observable using the Compact Muon Solenoid (CMS) at the LHC, and although produced at high momentum, it would travel slowly due to its large mass. We describe a search...
Christopher Marino
(University of Victoria)
04/06/2012, 16:00
Supersymmetry
Poster
A search for massive long-lived charged particles, performed using data recorded from pp collisions at sqrt(s) = 7 TeV collected by the ATLAS detector at the LHC, is presented. The velocity of high momentum particles is measured based on time-of-flight and anomalous ionisation energy loss, and the particle mass is estimated from the measured velocity and momentum. Based on a data sample using...
Yuichi Sasaki
(University of Tokyo (JP))
04/06/2012, 16:00
Supersymmetry
Poster
A search for supersymmetric particles using final states with one lepton, jets and a large missing momentum is presented. The analysis uses the full dataset (4.7 fb$^{-1}$) recorded by the ATLAS detector at $\sqrt{s} = 7$ TeV in 2011. The results are used to derive constraints on gluino and squark masses.
Estel Perez Codina
(TRIUMF (CA))
04/06/2012, 16:00
Supersymmetry
Poster
Results of a search for supersymmetry in events with at least four electrons or muons in the final state are presented. The search is performed in sqrt(s) = 7 TeV proton-proton collision data delivered by the LHC and recorded by ATLAS. Results are obtained in various signal regions and interpreted in terms of R-parity violating Minimal Supergravity models.
Niklas Andreas Pietsch
(UHH - Institute for Experimental Physics)
04/06/2012, 16:00
Supersymmetry
Poster
Motivated by supersymmetric models with light top and bottom squarks, a search for supersymmetry in final states with a single lepton, b-jets and missing transverse energy is performed. The analysis is based on data recorded at a center of mass energy of 7 TeV during 2011, corresponding to an integrated luminosity of 4.96/fb. Results are interpreted in the context of the constrained Minimal...
Noel Dawe
(SFU Simon Fraser University (CA))
04/06/2012, 16:00
Higgs Boson
Poster
Kathrin Becker
(Bergische Universitaet Wuppertal (DE))
04/06/2012, 16:00
Heavy Flavour Physics
Poster
The electroweak production of singly produced top quarks at the LHC operating at a center of mass energy of sqrt(s) = 7 TeV is dominated by the t-channel exchange of a virtual W boson that is emitted by a light quark inside one of the colliding protons. Thus, the measurement of the top-quark and top-antiquark production cross sections is sensitive to the u-quark PDF and the d-quark PDF for a...
Samuel King
(University of British Columbia (CA))
04/06/2012, 16:00
Supersymmetry
Poster
We present a search for supersymmetry and universal extra dimensions (UED) in events with three electrons or muons and missing transverse momentum. The analysis is based on sqrt(s) = 7 TeV proton-proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. The results are interpreted in a UED model and in terms of direct production of weak gauginos in...
Dr
Mario Martinez-Perez
(Universitat Autònoma de Barcelona (ES))
04/06/2012, 16:00
William Robert Spearman
(Harvard University (US))
04/06/2012, 16:00
Standard Model & Beyond
Poster
In 2012 the LHC will be operated in a mode leading to up to 40 inelastic pp collisions per bunch crossing, so-called "pile-up". The reconstruction and identification of muons produced in a hard collisions is difficult in this challenging environment. Di-muon decays of J/psi mesons and Z bosons have been used to study the muon reconstruction and identification efficiency of the ATLAS detector...
Christopher Hearty
(University of British Columbia)
04/06/2012, 16:00
Heavy Flavour Physics
Poster
Mihai Cuciuc
(Horia Hulubei National Institute of Physics and Nuclear Enginee)
04/06/2012, 16:00
Standard Model & Beyond
Poster
The Tile Calorimeter (TileCal), the central section of the hadronic calorimeter of the ATLAS experiment, is a key detector component to detect hadrons, jets and taus and to measure the missing transverse energy. Due to the very good muon signal to noise ratio it assists the spectrometer in the identification and reconstruction of muons. TileCal is built of steel and scintillating tiles coupled...
Silvia Borghi
(University of Glasgow (GB))
04/06/2012, 16:00
Heavy Flavour Physics
Poster
The LHCb experiment is designed to perform high-precision measurements of CP violation and search for New Physics using the enormous flux of beauty and charmed hadrons produced at the LHC. The operation and the results obtained from the data collected in 2010 and 2011 demonstrate that the detector is robust and functioning very well. However, the limit of ~1 fb–1 of data per year cannot be...
SUSIE Bedikian
(Yale University (US))
04/06/2012, 16:00
Standard Model & Beyond
Poster
Tau leptons play an important role in the physics program at the LHC. They are used not only in searches for new phenomena like the Higgs boson or Supersymmetry and electroweak measurements but also in detector related studies like the determination of the missing transverse energy scale. Optimal identification of hadronically decaying tau leptons is achieved by using detailed information from...
