Bulletin of the American Physical Society
2008 APS April Meeting and HEDP/HEDLA Meeting
Volume 53, Number 5
Friday–Tuesday, April 11–15, 2008; St. Louis, Missouri
Session M12: Top III |
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Sponsoring Units: DPF Chair: Chip Brock, Michigan State University Room: Hyatt Regency St. Louis Riverfront (formerly Adam's Mark Hotel), St. Louis C |
Sunday, April 13, 2008 3:30PM - 3:42PM |
M12.00001: Top quark mass measurement in the lepton+jets channel at CDF using a mulitvariate template method Paul Lujan We present a preliminary measurement of the top quark mass using data collected by the CDF II detector at the Fermilab Tevatron from $p\bar p$ collisions at $\sqrt(s)$ = 1.96 GeV. We reconstruct $t\bar t$ events in the lepton + jets channel using a multivariate template method, which uses a matrix element integration with transfer functions relating jet and parton momentum to build a likelihood function for each event as a function of top mass. An additional likelihood cut is used to reject background and poorly-modeled signal events, improving our overall resolution in constructing the final likelihood function to determine the overall top quark mass value. [Preview Abstract] |
Sunday, April 13, 2008 3:42PM - 3:54PM |
M12.00002: Measurement of the ttbar Production Cross Section at D0 Using lepton+jets events Sehwook Lee We report on the measurement of the ttbar production cross section using candidate events in the lepton+jets final state. We separate the signal from background processes using kinematic information or a neural network algorithm that uses lifetime information to identify the b-quark jets. [Preview Abstract] |
Sunday, April 13, 2008 3:54PM - 4:06PM |
M12.00003: Measurement of the Top Quark Mass at D0 Using the Matrix-Element Method in the Lepton+Jets Channel Zhenyu Ye We report on the measurement of the top quark mass using candidates in the lepton+jets final state. For each event, a probability based on the differential cross section for production is calculated as a function of the top mass and the overall jet energy scale. The top mass and jet energy scale are extracted by maximizing a likelihood constructed as the product of the single event probabilities. The overall jet energy scale is constrained by the two jets from the hadronic W boson decay. [Preview Abstract] |
Sunday, April 13, 2008 4:06PM - 4:18PM |
M12.00004: Top quark mass measurement in the lepton+jets and dilepton channels at CDF using a template method Hyun Su Lee We present a measurement of the top quark mass using the CDF detector at the Fermilab Tevatron in a 2 fb$^{-1}$ data sample observed in the lepton+jets and two leptons final states. In the lepton+jets channel, we determine the reconstructed top quark invariant mass in each event by minimizing a $\chi^2$ for the overconstrained kinematic system. At the same time, we measure the mass of the hadronically decaying $W$ boson in the same event sample, that provides an in situ improvement in the determination of the jet energy scale. In the dilepton channel, the reconstruction of the top quark mass involves an under-constrained system due to two neutrinos in each event. We integrate undetermined kinematic variables and produce a probability distribution which gives the relative likelihood of different values of the top quark mass. We extract the top quark mass and the jet energy scale by comparing representative distributions constructed from simulated events to the data distribution. We simultaneously fit for the top quark mass and the jet energy scale using two observables in the lepton + jets and dilepton channels with a single likelihood. [Preview Abstract] |
Sunday, April 13, 2008 4:18PM - 4:30PM |
M12.00005: Measurement of the Top Quark Mass at D0 Using the Ideogram Method in the Lepton+Jets Channel Amnon Harel We report on the measurement of the top quark mass based on a 1 fb~$^{-1}$ sample of ttbar events in the lepton+jets final state. For each event, a probability based on the kinematic reconstruction of the event is calculated as a function of the top mass and the overall jet energy scale. The top mass and jet energy scale are extracted by maximizing a likelihood constructed as the product of the single event probabilities. The overall jet energy scale is constrained by the two jets from the hadronic W boson decay. [Preview Abstract] |
Sunday, April 13, 2008 4:30PM - 4:42PM |
M12.00006: ABSTRACT WITHDRAWN |
Sunday, April 13, 2008 4:42PM - 4:54PM |
M12.00007: Measurement of the top production cross section rate from gluon-gluon fusion at CDF Jared Yamaoka We present a measurement of the ratio of top-antitop production cross section via gluon-fusion to the total production cross section in proton-antiproton collisions with $\sqrt(s)$ = 1.96 TeV at the Fermilab Tevatron. The data sample, recorded by CDF II, has an integrated luminosity of 955 pb$^{-1}$. Using an artificial neural network trained on the kinematics to discriminate the gluon-fusion events, we find the ratio of the gluon-fusion cross section to the total cross section to be $<0.33$ at the 68$\%$ confidence level and $< 0.61$ at the 95$\%$ confidence level. Additionally, we combine this measurement with a complementary analysis using the charged particle multiplicity in top-antitop evens and find the ratio to be 0.07+0.15-0.07. [Preview Abstract] |
Sunday, April 13, 2008 4:54PM - 5:06PM |
M12.00008: Measurement of the top production cross section using events with large missing transverse energy and bottom quark jets at CDF Gabriele Compostella 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 the CDF II Detector at the Fermilab Tevatron. We study events with high missing transverse energy and we select those that contain jets that are identified in the silicon vertex detector as originating from $b$-quarks using a neural network algorithm. [Preview Abstract] |
Sunday, April 13, 2008 5:06PM - 5:18PM |
M12.00009: ABSTRACT WITHDRAWN |
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