A Measurement Of The T Bar T Production Cross Section In P Bar P Collisions At U221a S
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Measurement Of The T Bar T Production Cross Section In P Bar P Collisions At U221a S
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Author :
language : en
Publisher:
Release Date : 2005
Measurement Of The T Bar T Production Cross Section In P Bar P Collisions At U221a S written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005 with categories.
We present the measurement of the t$ar{t}$ cross section in the lepton plus jets channel with ≥ 1 and ≥ 2 secondary vertex tags. We use the scalar sum of transverse energies of the event (HT) to discriminate t{bar t} from the other backgrounds. We also use the transverse mass of the leptonic W-boson (M$Wtop{T}$) to further reduce the Non-W backgrounds. We use a combination of data and Monte Carlo to estimate the backgrounds from electroweak processes, single top, fake leptons, W+ Light Flavor fake tags, and real W+ Heavy Flavor production. We obtain a value of ? ≥1 = 8.7$+0.9top{-0.9}$(stat)$+1.2top{-0.9}$(sys) pb for the ≥1 tag cross section, and ? ≥2 = 8.7$+1.8top{-1.6}$(stat)$+1.9top{-1.3}$(sys) pb for the ≥2 tag cross section. The authors also present a measurement of the t$ar{t}$ cross section by fitting the Njet spectrum. They combine the =1 and ≥2 tag cross sections to obtain ?t$ar{t}$ = 8.9$+0.9top{-0.9}$(stat)$+1.4top{-1.3}$(syst)pb.
A Measurement Of The Production Cross Section Of T Bar T In P Bar P Collisions At U221a S
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Author :
language : en
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Release Date : 2004
A Measurement Of The Production Cross Section Of T Bar T In P Bar P Collisions At U221a S written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2004 with categories.
A measurement of the t$\bar{t}$ pair production cross section is presented using 162 pb -1 of data collected by the CDF experiment during Run II at the Tevatron. t$\bar{t}$} events in the lepton+jets channel are isolated by identifying electrons and muons, reconstructing jets and transverse missing energy, and identifying b jets with a secondary vertex tagging algorithm. The efficiency of the algorithm is measured in a control sample using a novel technique that is less dependent on the simulation. For a top quark mass of 175 GeV/c2 , a cross section of ?t$\bar{t}$ = 5.6$+1.2\atop{-1.1}$(stat.)$+0.9\atop{-0.6}$(syst.)pb is measured.
A Measurement Of The T Bar T Production Cross Section In P Bar P Collisions At U221a S
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Author :
language : en
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Release Date : 2008
A Measurement Of The T Bar T Production Cross Section In P Bar P Collisions At U221a S written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008 with categories.
I present a measurement of the t$ar{t}$ production cross section at √s = 1.96 TeV using 2034 pb-1 of CDF Run II data using events with a high transverse momentum electron or muon, three or more jets, and missing transverse energy. The measurement assumes a t → Wb branching fraction of 100 percent. Events consistent with t$ar{t}$ decay are found by identifying jets containing heavy-flavor semileptonic decays to muons. The dominant backgrounds are evaluated directly from the data. Based on 248 candidate events and an expected background of 86.8 ± 5.6 events, I measure a production cross section of 8.7 ± 1.1$+0.9top{-0.8}$ ± 0.6 pb, in agreement with the Standard Model.
Measurement Of The T Bar T Cross Section Using The Dimuon Channel In P Bar P Collisions At U221a S
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language : en
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Release Date : 2004
Measurement Of The T Bar T Cross Section Using The Dimuon Channel In P Bar P Collisions At U221a S written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2004 with categories.
The author has measured the t$ar{t}$ production cross section at √s = 1.96 TeV using data collected by the D0 experiment at Fermilab. The integrated luminosity of the data set is 140 pb-1 and a total of four candidate events are seen, with an expected background of 2.61 events. The measured cross section of ?t$ar{t}$ = 11.1$+22.1top{-9.3}$(stat.)$+4.3top{-4.5}$(sys.) pb is in agreement with a NNLO calculation of 6.77 pb.
Measurement Of The T Tbar Production Cross Section In P Pbar Collisions At U221a S
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language : en
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Release Date : 2006
Measurement Of The T Tbar Production Cross Section In P Pbar Collisions At U221a S written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006 with categories.
The top quark is the most massive fundamental particle observed so far, and the study of its properties is interesting for several reasons ranging from its possible special role in electroweak symmetry breaking to its sensitivity to physics beyond the standard model (SM). In particular, the measurement of the top quark pair production cross section ?t$ar{t}$ is of interest as a test of QCD predictions. Recent QCD calculations done with perturbation theory to next-to-leading order predict ?t$ar{t}$ with an uncertainty of less than 15%, which motivate measurements of comparable precision. In this thesis, the author reports a measurement of the cross section for pair production of top quarks in the lepton+jets channel in 318 pb-1 of p$ar{p}$ collision data at √s = 1.96 TeV. The data were recorded between March 2002 and September 2004, during Run II of the Tevatron, by the CDF II detector, a general purpose detector which combines charged particle trackers, sampling calorimeters, and muon detectors. processes in which a W boson is produced in association with several jets with large transverse momentum can be misidentified at t$ar{t}$, since they have the same signature. In order to separate the t$ar{t}$ events from this background, they develop a method to tag b-jets based on tracking information from the silicon detector. The main event selection requires at least one tight (more restrictive) b tag in the event. As a cross check, they also measure the cross section using events with a loose (less restrictive) b tag and events which have at least two tight or at least two loose b tags. Background contributions from heavy flavor production processes, such as Wb$ar{b}$, Wc$ar{c}$ or Wc, misidentified W bosons, electroweak processes, single top production, and mistagged jets are estimated using a combination of Monte Carlo calculations and independent measurements in control data samples. An excess over background in the number of events that contain a lepton, missing energy and three or more jets with at least one b-tag is assumed to be a signal of t$ar{t}$ production and is used to measure the production cross section ?t$ar{t}$.
Measurement Of The Top Quark Pair Production Cross Section In P Anti P Collisions At U221a S
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language : en
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Release Date : 2006
Measurement Of The Top Quark Pair Production Cross Section In P Anti P Collisions At U221a S written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006 with categories.
The subject of this thesis is the measurement of the rate at which a top-antitop quark pair is produced in pp collisions at a center of mass energy of ps = 1:96 TeV. The data are collected with the D detector, a multi-purpose detector operating at the Fermilab Tevatron collider during Run II. A measurement of the top quark pair (t$\bar{t}$) production cross section ( ?t$\bar{t}$) in p$\bar{p}$ collisions at a center of mass energy of 1.96 TeV is presented. The measurement is based on data recorded by the D0 Detector at the Fermilab Tevatron Collider, and preselected in the e+jets (366 pb-1) and ?+jets (363 pb-1) channels. The cross section is extracted by applying a lifetime-tagging technique to the data, and yields ?t$\bar{t}$ = 6.96$+1.07\atop{-0.98}$(stat + syst) ± 0.45(lumi) pb; for a top quark mass mt =175 GeV, in good agreement with the Standard Model prediction.
Measurement Of The T Bar T Production Cross Section In P Bar P Collisions At Sqrt S
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Author :
language : en
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Release Date : 2011
Measurement Of The T Bar T Production Cross Section In P Bar P Collisions At Sqrt S written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.
In this paper we report a measurement of the t{anti t} production cross section in p{anti p} collisions at √{ovr s} = 1.96 TeV using data corresponding to an integrated luminosity of 2.2 fb−1 collected with the CDF II detector at the Tevatron accelerator. We select events with significant missing transverse energy and high jet multiplicity. This measurement vetoes the presence of explicitly identified electrons and muons, thus enhancing the tau contribution of t{anti t} decays. Signal events are discriminated from the background using a neural network and heavy flavor jets are identified by a secondary-vertex tagging algorithm. We measure a t{anti t} production cross section of 7.99 ± 0.55 (stat) ± 0.76 (syst) ± 0.46 (lumi) pb, assuming a top mass m{sub top} = 172.5 GeV/c2, in agreement with previous measurements and standard model predictions.
Measurement Of The T Bar T Ww And Z U2192 Production Cross Sections In P Bar P Collisions At U221a S
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language : en
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Release Date : 2006
Measurement Of The T Bar T Ww And Z U2192 Production Cross Sections In P Bar P Collisions At U221a S written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006 with categories.
In this thesis we present a new technique to analyze events containing two highly energetic leptons, as a probe of the Standard Model. The philosophy is to consider the data in a more global way, as opposed to the more traditional process dependent approach of extracting a given signal over the expected backgrounds by using various kinematical requirements. We use our global technique to simultaneously measure the cross sections of the main Standard Model processes; the t$ar{t}$, WW and Z → ?? production from p$ar{p}$ collisions at √s = 1.96 TeV in the CDF detector at Fermilab. We select events by requiring they contain two highly energetic leptons (e?, ee, or ??), and make no other kinematic requirements, except for the ee and ?? channels. We then use a likelihood fit of the data in the two-dimensional phase space defined by the missing transverse energy (ET) and the number of jets in the event (Njet), to the expected Standard Model distributions, to simultaneously extract the production cross-sections of the main process contributing to our dilepton sample.
Measurement Of The T Anti T Production Cross Section In P Anti P Collisions At S
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Author :
language : en
Publisher:
Release Date : 2006
Measurement Of The T Anti T Production Cross Section In P Anti P Collisions At S written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006 with categories.
We report a new measurement of the t{bar t} production cross section in p{bar p} collisions at a center-of-mass energy of 1.96 TeV using events with one charged lepton (electron or muon), missing transverse energy, and jets. Using 425 pb−1 of data collected using the D0 detector at the Fermilab Tevatron Collider, and enhancing the t{bar t} content of the sample by tagging b jets with a secondary vertex tagging algorithm, the t{bar t} production cross section is measured to be:?{sub p{bar p} → t{bar t}+X} = 6.6 ± 0.9(stat + syst) ± 0.4(lum) pb. This cross section is the most precise D0 measurement to date for t{bar t} production and is in good agreement with standard model expectations.
Measurement Of The T Anti T Production Cross Section In P Anti P Collisions At S 1 2
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Author :
language : en
Publisher:
Release Date : 2006
Measurement Of The T Anti T Production Cross Section In P Anti P Collisions At S 1 2 written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006 with categories.
We report a new measurement of the t{bar t} production cross section in p{bar p} collisions at a center-of-mass energy of 1.96 TeV using events with one charged lepton (electron or muon), missing transverse energy, and jets. Using 425 pb−1 of data collected using the D0 detector at the Fermilab Tevatron Collider, and enhancing the t{bar t} content of the sample by tagging b jets with a secondary vertex tagging algorithm, the t{bar t} production cross section is measured to be: [sigma]{sub p{bar p} → t{bar t}+X} = 6.6 ± 0.9(stat + syst) ± 0.4(lum) pb. This cross section is the most precise D0 measurement to date for t{bar t} production and is in good agreement with standard model expectations.