Bulletin of the American Physical Society
2006 Texas Section of the APS Joint Fall Meeting
Thursday–Saturday, October 5–7, 2006; Arlington, Texas
Session HEP2: High Energy Physics II |
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Chair: Fred Olness, Southern Methodist University Room: UT Arlington, University Center Guadalupe |
Saturday, October 7, 2006 10:30AM - 10:42AM |
HEP2.00001: Studies of the CMS Hadron Calorimeter Response to Low Energy Electron and Pion Beams Youn Roh, Nural Akchurin, Sung-Won Lee In this talk we present the response of a prototype CMS hadron calorimeter module to low energy charged particle beams of pions, muons and electrons with momenta down to 2 GeV/c. The data were taken at the H2 beam-lines at CERN in 2006 summer. The effects of electromagnetic calorimeter on the linearity and energy resolution of the combined calorimeter system to hadrons is also studied. [Preview Abstract] |
Saturday, October 7, 2006 10:42AM - 10:54AM |
HEP2.00002: Central Exclusive Higgs Production Arnab Pal, Andrew Brandt First simulation results for Central Exclusive Higgs Production will be presented. This process, to be studied at the LHC using newly proposed proton taggers, provides a promising complementary means of discovering and characterizing the Higgs Boson. [Preview Abstract] |
Saturday, October 7, 2006 10:54AM - 11:06AM |
HEP2.00003: SUSY-Cosmology at the LHC Alfredo Gurrola, Richard Arnowitt, Bhaskar Dutta, Teruki Kamon, Nikolay Kolev, Abram Krislock, Paul Simeon Supersymmetry (SUSY) is a very attractive theory of particle physics that could connect to cosmology and explain the early universe. With an assumption of the lightest supersymmetric neutral gauge boson (neutralino) to be a dark matter (DM), the recent measurement of the amount of DM of the universe with other experimental results constrains a SUSY parameter space where a mass difference between the supersymmetric tau lepton (stau) and the neutralino is very small (5 to 15 GeV). The Large Hadron Collider (LHC) will produce the SUSY events copiously and contain two or more tau leptons in the final state. We systematically study an experimental requirement of measuring the characteristic mass difference at the LHC. Within a benchmark framework of minimal supergravity, we confirm the conclusion in our previous publication that the tau lepton must be identified with a transverse energy above 20 GeV. [Preview Abstract] |
Saturday, October 7, 2006 11:06AM - 11:18AM |
HEP2.00004: Testing Gaugino Universality in Minimal Supergravity at the LHC Abram Krislock, Richard Arnowitt, Bhaskar Dutta, Alfredo Gurrola, Teruki Kamon, Nikolay Kolev, Paul Simeon SUSY is a leading theory to uniquely open the possibility of unification of fundamental forces. As a result, the well motivated minimal supergravity (mSUGRA) models predict a particular mass relation among the three kinds of supersymmetric gauge bosons (gluino, next-to-lightest neutralino, and the lightest neutralino). The relation, originated by gaugino mass universality, will give an insight of Grand Unified Theories. The previous study showed that we will have to identify the tau lepton with a transverse energy above 20 GeV to probe the cosmologically allowed mSUGRA parameter space at the LHC. We extend the study by investigating a methodology of testing the mass universality hypothesis as well as the maximum reach of the gaugino masses. [Preview Abstract] |
Saturday, October 7, 2006 11:18AM - 11:30AM |
HEP2.00005: Low-Energy Tau Identification for Probing SUSY-Cosmology at the LHC Paul Simeon, Richard Arnowitt, Bhaskar Dutta, Alfredo Gurrola, Teruki Kamon, Nikolay Kolev, Abram Krislock For probing supersymmetric cosmology at the LHC, both ATLAS and CMS experiments will have to identify tau leptons with a transverse energy above 20 GeV. The experimental first step before such SUSY search program is to observe tau-lepton pair from Z boson decay. This observation will guarantee the quality of the tau lepton identification (ID) at the LHC experiments. In order to design the tau ID, we study the hadronic decays of tau leptons in the Z bosons in the LHC envi-ronment using PYTHIA and TAUOLA Monte Carlo programs. Our preliminary study shows that the one-prong hadronic decay is most suitable for maximizing tau ID efficiency and minimizing misidentified taus. [Preview Abstract] |
Saturday, October 7, 2006 11:30AM - 11:42AM |
HEP2.00006: Non-Unitary Evolution in Discrete Hilbert Space Randy Huegele The assumption of continuous space and time (or spacetime) commonly used in physical theories requires systems of finite volume and energy to contain infinite information.~ Black hole entropy suggests that the information capacity of matter and energy confined to any region of space is finite and bounded above by the surface area of the Schwarzschild radius of \underline {a black hole enclosing the system}.~ A theory of discrete spacetime would resolve this problem by only allowing finite information in a region of space.~ Discrete spacetime requires discrete, \underline {finite-dimensional} Hilbert space where unitary evolution is supplanted by measurement operations whose mild non-unitarity corresponds to the granularity of the spacetime.~ The physical implications of this discrete spacetime theory are discussed. [Preview Abstract] |
Saturday, October 7, 2006 11:42AM - 11:54AM |
HEP2.00007: Physics Capabilities of the PHENIX Muon Trigger Upgrade Rusty Towell While significant progress has been made in understanding the structure of the nucleon, many important questions remain including the origin of the proton spin. Plans have been made to develop a new state-of-the-art trigger system for the PHENIX muon arms. With this new system a precise measurement of the flavor structure of the quark polarizations in the proton can be made via the observations of W-bosons in polarized proton-proton collisions. W-bosons can be detected in PHENIX through the appearance of a high-energy muon in one of the two existing muon spectrometers. The trigger upgrade is based on fast resistive plate counter stations. Prototypes of these chambers have been made and tested. This talk will describe the status of the upgrade and some of the physics results that can be expected. [Preview Abstract] |
Saturday, October 7, 2006 11:54AM - 12:06PM |
HEP2.00008: A search for Wb$\rm\bar{b}$ and WH production in p$\rm\bar{p}$ collisions at $\rm\sqrt{s}$=1.96 TeV using 1f$\rm b^{-1}$ of data. Venkatesh Kaushik, Jaehoon Yu, Hyunwoo Kim A search for Wb$\rm\bar{b}$ and WH production in p$\rm\bar{p}$ collisions at a center of mass energy of $\rm\sqrt{s}$ = 1.96 TeV is presented. Events containing one isolated electron, missing transverse energy and one or two b-tagged jets are considered. The integrated luminosity accumulated by the D$\O$ experiment at the Tevatron collider corresponds to 1.0{\rm fb$^{-1}$}. In the double b-tagged sample, good agreement between data and the Standard Model is achieved only when Wb$\rm\bar{b}$ production is included. Since we cannot establish its presence with high significance yet, we establish a 95\% C.L. upper limit on the Wb$\rm\bar{b}$ production cross section by requiring b jets with transverse momenta \rm{$p_T$} $>$ 20 GeV and a pseudorapidity $\eta <$ 2.5. The upper limit on WH production cross section is obtained by requiring additional selection on the b$\rm\bar{b}$ invariant mass to minimize Wb$\rm\bar{b}$ background contributions to the Higgs signal. Since its mass is unknown, Higgs masses in the range of 115 GeV/$\rm c^2$ to 155 GeV/$\rm c^2$ are scanned to establish the upper limit. [Preview Abstract] |
Saturday, October 7, 2006 12:06PM - 12:18PM |
HEP2.00009: Implementation of Vertex Reconstruction in the Search for Resonances in the 1610-1770 MeV Invariant Mass Region Ezekiel Walker In recent years, there has been considerable activity in the realm of baryon spectroscopy. A collaboration between Petersburg Nuclear Physics Institute (PNPI), Institute for Theoretical and Experimental Physics (ITEP), and Abilene Christian University (ACU), is aimed at increasing the understanding of the 1610-1770 MeV invariant mass region. ACU is particularly interested in the N*(1710) resonance, a poorly defined excited state of the nucleon. Utilizing GEANT4 and ROOT, two powerful simulation and analysis programs, ACU is simulating the $\pi ^{-}$p -$> \quad {\rm K}\Lambda $ reaction to help find the optimum design parameters for the experiment. In order to reconstruct the $\pi ^{-}$p -$> \quad {\rm K}\Lambda $ events, a vertex reconstruction algorithm was designed, tested, and implemented. An overview of the design process, capabilities, limitations, and current results will be discussed. [Preview Abstract] |
Saturday, October 7, 2006 12:18PM - 12:30PM |
HEP2.00010: Charge Pre-Amplifier Functionality in Gas Electron Multiplier Digital Hadron Calorimeter at UTA Heather Brown, Changhie Hahn, Wonjeong Kim, Jia Li, Carlos Medina, Akihiro Nozawa, Jacob Smith, Andy White, Jaehoon Yu A digital hadron calorimeter (DHCAL) is a sampling calorimeter that could provide the necessary jet energy resolution for International Linear Collider physics when used with the Particle Flow Algorithms (PFA). UTA's High Energy Physics (HEP) group has been developing a DHCAL using Gas Electron Multiplier (GEM) technology. GEM amplifies energy deposit from traversing charged particles using a high electric field applied across a copper-clad thin plastic foil. Given its hole spacing, GEM can resolve individual particles in a hadronic shower down to $\mu $m level. The components under consideration in this presentation are the output electronics, specifically, the charge pre-amplifiers supplied by Fermi National Accelerator Laboratory. In order for us to test GEM chambers, we need to make sure that all pre-amplifier cards function properly. In this study, we will present the plans for the beam tests, GEM chamber structure, test and certification procedure for the pre-amplifiers and the result of the tests. [Preview Abstract] |
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