Bulletin of the American Physical Society
2005 APS April Meeting
Saturday–Tuesday, April 16–19, 2005; Tampa, FL
Session T7: Top Quark Pair Production II |
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Sponsoring Units: DPF Chair: Tim Tait, Argonne National Laboratory Room: Marriott Tampa Waterside Room 1 |
Monday, April 18, 2005 1:30PM - 1:42PM |
T7.00001: Simulation of Top Quark Pair Production as a Background for Higgs Events at the Compact Muon Solenoid Christopher Justus, James Dolen, Regina Demina In this study, we simulated top-antitop (tt-bar) quark events at the Compact Muon Solenoid (CMS), an experiment presently being constructed at the Large Hadron Collider in Geneva, Switzerland. The tt-bar process is an important background for Higgs events. We used a chain of software to simulate and reconstruct processes that will occur inside the detector. CMKIN was used to generate and store Monte Carlo Events. OSCAR, a GEANT4 based CMS detector simulator, was used to simulate the CMS detector and how particles would interact with the detector. Next, we used ORCA to simulate the response of the readout electronics at CMS. Last, we used the Jet/MET Root maker to create root files of jets and missing energy. We are now using this software analysis chain to complete a systematic study of initial state radiation at hadron colliders. This study is essential because tt-bar is the main background for the Higgs boson and these processes are extremely sensitive to initial state radiation. Results of our initial state radiation study will be presented. We started this study at the new LHC Physics Center (LPC) located at Fermi National Accelerator Laboratory, and we are now completing the study at the University of Rochester. [Preview Abstract] |
Monday, April 18, 2005 1:42PM - 1:54PM |
T7.00002: Measurement of the t$\bar{t}$ Production Cross-Section in Dilepton Events with Secondary Vertex b-tagging Alexei Varganov We report on a measurement of the $t\bar{t}$\ production cross section in 340 pb$^{-1}$\ of $t\bar{t}$\ events collected with the CDF detector at the Tevatron containing two identified high p$_T$\ leptons, missing energy and at least one $b$-jet candidate. We reconstruct b-jets using secondary vertices in the silicon vertex detecor. By adding the b-quark identification we can relax some of the selection criteria used to identify top decay in the dilepton channel while keeping the non top contamination to a minimum. We finally compare selected kinematic properties of these events with the prediction of the Standard Model for the $t\rightarrow Wb$\ vertex. [Preview Abstract] |
Monday, April 18, 2005 1:54PM - 2:06PM |
T7.00003: Measurement of top pair production cross section in Lepton plus Jets events at CDF with event kinematics. Kevin Lannon A major goal of the CDF physics program at the Tevatron is the precise measurement of the properties of the top quark. We present a measurement of the $t\bar t$ production cross section in $p\bar{p}$ collisions at $\sqrt{s}$ = 1.96 TeV, using 340 pb$^{-1}$ of data collected by the CDFII detector at the Fermilab Tevatron. We select events with a high transverse momentum electron or muon, 3 or more jets, and missing $E_T$. We develop an artifical neural network method that uses a variety of kinematic quantities to distinguish $t\bar{t}$\ events from the primary background of W boson production with associated jets. [Preview Abstract] |
Monday, April 18, 2005 2:06PM - 2:18PM |
T7.00004: $t\bar{t}$\ Cross-section Measurement into Multi-Jet Final States Giorgio Cortiana We present a $t\bar{t}$\ production cross section measurement in the multi-jet final state channel from collisions of protons and anti-protons at 1.96 TeV at the Collider Detector at Fermilab (CDF). We study events, selected using optimized kinematical criteria, that contain jets that are identified in the Silicon Vertex Detector as originating from b-quarks. Contributions to the measurement from events with hadronically decaying taus are also discussed. [Preview Abstract] |
Monday, April 18, 2005 2:18PM - 2:30PM |
T7.00005: Measurement of the $t\bar t$ Production Cross Section in $p\bar p $ Collisions at $\sqrt{s}=1.96$ TeVUsing Lepton Plus Jets Events with Secondary Vertex b-Tagging Sal Rappoccio We present a preliminary measurement of the $t\bar{t}$ pair production cross section in $p\bar{p}$ collisions at $\sqrt{s}$ = 1.96 TeV using 340 pb$^{-1}$ of data collected by the CDFII detector at the Fermilab Tevatron. We measure the cross section in events with one high high transverse momentum lepton and 3 or more jets, where at least one $b$-jet is identified via a displaced vertex algorithm. [Preview Abstract] |
Monday, April 18, 2005 2:30PM - 2:42PM |
T7.00006: Measurement of the $t\bar t$ Production Cross Section in $p\bar p $ Collisions at $\sqrt{s}=1.96$ TeV Using Lepton Plus Jets Events with Soft Muon b-Tagging Ulysses Grundler We present a measurement of the $t\bar t$ production cross section in $\sim 200 \mathrm{pb^{-1}}$ of CDF Run 2 data using events with a high transverse momentum electron or muon, 3 or more jets, and missing $E_T$. Events consistent with $t\bar t$ decay are found by identifying jets containing candidate heavy- flavor semileptonic decays to muons. Backgrounds are computed from a combination of Run 2 data and simulation. Signal acceptance is determined from Run 2 $t \bar t$ PYTHIA Monte Carlo. Based on 20 candidate events with 3 or more jets and an expected background of 9.6 events, a production cross section of $5.2^{+2.9~+1.3}_{-1.9~-1.0}~\mathrm{pb}$ is measured. [Preview Abstract] |
Monday, April 18, 2005 2:42PM - 2:54PM |
T7.00007: Measurement of $t\bar t$ production cross section in the lepton+jets channel using Jet Probability $b$-tagging at CDF Enrique Palencia We present a preliminary measurement of the $t\bar t$ pair production cross section in the collisions of protons and anti-protons at 1.96\~TeV at the Collider Detector at Fermilab (CDF). The measurement uses $t\bar t$ decays into final states which contain one high transverse momentum lepton and multiple jets, where one of the jets is required to be identified as a $b$-jet candidate from the information of the trackĀ“s impact parameter resolution using the SVXII Silicon Vertex detector. The performance of the tagging algorithm used in this analysis is also discussed. [Preview Abstract] |
Monday, April 18, 2005 2:54PM - 3:18PM |
T7.00008: Combination of top pair production cross sections at CDF. Charles Plager A major goal of the CDF physics program at the Tevatron is the precise measurement of the properties of the top quark. We discuss the gain in precision from combination of the various CDF measurements of the $t\bar t$\ production cross section in $p\bar{p}$\ collisions at $\sqrt{s}$\ = 1.96 TeV. We present the combined cross section using 340 pb$^{-1}$\ of data collected by the CDFII detector at the Fermilab Tevatron. [Preview Abstract] |
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