› › Measurement Of The Tanti T Production Cross Section In P Anti Ptnipbar Collisions At S**1 2

Measurement of the Tanti-t Production Cross Section in P Anti-ptnipbar Collisions at S**1/2

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Page : 7 pages

File Size : 20,12 MB

Release : 2006

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The authors present a measurement of the top quark pair production cross section in p{bar p} collisions at √s = 1.96 TeV using 318 pb−1 of data collected with the Collider Detector at Fermilab. They select t{bar t} decays into the final states e[nu] + jets and [mu][nu] + jets, in which at least one b quark from the t-quark decays is identified using a secondary vertex-finding algorithm. Assuming a top quark mass of 178 GeV/c2, they measure a cross section of 8.7 ± 0.9(stat.){sub -0.9}{sup +1.1}(syst.) pb. They also report the first observation of t{bar t} with significance greater than 5[sigma] in the subsample in which both b quarks are identified, corresponding to a cross section of 10.1{sub -1.4}{sup +1.6}(stat.){sub -1.3}{sup +2.0}(syst.) pb.



A Measurement of the T Anti-t Production Cross Section in P Anti-p Collisions at S**1/2

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Page : 131 pages

File Size : 45,52 MB

Release : 2008

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I present a measurement of the t{bar 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{bar 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{sub -0.8}{sup +0.9} ± 0.6 pb, in agreement with the Standard Model.



Measurement of the T Anti-t Production Cross Section in P Anti-p Collisions at S**(1/2)

Author : Lucio Cerrito

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Page : 4 pages

File Size : 34,36 MB

Release : 2005

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We present two measurements of the t{bar t} production cross section in collisions of protons and antiprotons at {radical}s = 196 TeV. We analyze a dataset of 310 {+-} 20 pb{sup -1} collected with the CDF 2 detector. In the first measurement, we select events with six to eight jets, at least one of which having a displaced secondary vertex, little or no missing transverse energy and optimized kinematical criteria consistent with the t{bar t} all-hadronic decay channel. In the second measurement, we select events with four or more jets, at least one of which having a displaced secondary vertex, high missing transverse energy, and optimized kinematical criteria consistent with the decay of t{bar t} to {tau}+jets. The averaged t{bar t} production cross section, determined from six different measurements using the CDF 2 detector in the dilepton, lepton+jets and all-hadronic decay channels, is also calculated to be {sigma}{sub t{bar t}} = 7.1 {+-} 0.6(stat) {+-} 0.7(syst) {+-} 0.4(lumi) pb, in agreement with the prediction of the standard model.



Measurement of the T Anti-t Production Cross Section in P Anti-p Collisions at S**(1/2)

Author : Salvatore Rocco Rappoccio

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Page : 377 pages

File Size : 46,71 MB

Release : 2005

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We present the measurement of the t{bar t} cross section in the lepton plus jets channel with {ge} 1 and {ge} 2 secondary vertex tags. We use the scalar sum of transverse energies of the event (H{sub T}) to discriminate t{bar t} from the other backgrounds. We also use the transverse mass of the leptonic W-boson (M{sub T}{sup W}) 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 {sigma} {sub {ge}1} = 8.7{sub -0.9}{sup +0.9}(stat){sub -0.9}{sup +1.2}(sys) pb for the {ge}1 tag cross section, and {sigma}{sub {ge}2} = 8.7{sub -1.6}{sup +1.8}(stat){sub -1.3}{sup +1.9}(sys) pb for the {ge}2 tag cross section. The authors also present a measurement of the t{bar t} cross section by fitting the N{sub jet} spectrum. They combine the =1 and {ge}2 tag cross sections to obtain {sigma}{sub t{bar t}} = 8.9{sub -0.9}{sup +0.9}(stat){sub -1.3}{sup +1.4}(syst)pb.



Measurement of the T Anti-t Production Cross Section in P Anti-p Collisions at S**1/2

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Page : 25 pages

File Size : 11,99 MB

Release : 2006

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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.





Measurement of the T Anti-t Production Cross Section in P Anti-p Collisions at S**ư

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Page : 4 pages

File Size : 46,73 MB

Release : 2005

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We present two measurements of the t{bar t} production cross section in collisions of protons and antiprotons at √s = 196 TeV. We analyze a dataset of 310 ± 20 pb−1 collected with the CDF 2 detector. In the first measurement, we select events with six to eight jets, at least one of which having a displaced secondary vertex, little or no missing transverse energy and optimized kinematical criteria consistent with the t{bar t} all-hadronic decay channel. In the second measurement, we select events with four or more jets, at least one of which having a displaced secondary vertex, high missing transverse energy, and optimized kinematical criteria consistent with the decay of t{bar t} to?+jets. The averaged t{bar t} production cross section, determined from six different measurements using the CDF 2 detector in the dilepton, lepton+jets and all-hadronic decay channels, is also calculated to be?{sub t{bar t}} = 7.1 ± 0.6(stat) ± 0.7(syst) ± 0.4(lumi) pb, in agreement with the prediction of the standard model.



Top Physics

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Page : 28 pages

File Size : 16,98 MB

Release : 2005

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We present a measurement of the t{bar t} production cross section using events with one charged lepton and jets from p{bar p} collisions at a center-of-mass energy of 1.96TeV. In these events, heavy flavor quarks from top quark decay are identified with a secondary vertex tagging algorithm. From 162 pb−1 of data collected by the Collider Detector at Fermilab, a total of 48 candidate events are selected, where 13.5 ± 1.8 events are expected from background contributions. We measure a t{bar t} production cross section of 5.6{sub -1.1}{sup _1.2}(stat.){sub -0.6}{sup +0.9}(syst.)pb.



Measurement of the P Anti-p --] T Anti-t Production Cross Section at S**1/2

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Page : 10 pages

File Size : 43,80 MB

Release : 2006

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A measurement of the top quark pair production cross section in proton anti-proton collisions at an interaction energy of √s = 1.96 TeV is presented. This analysis uses 405 pb−1 of data collected with the D0 detector at the Fermilab Tevatron Collider. Fully hadronic t{bar t} decays with final states of six or more jets are separated from the multijet background using secondary vertex tagging and a neural network. The t{bar t} cross section is measured as [sigma]{sub t{bar t}} = 4.5{sub -1.9}{sup +2.0}(stat){sub -1.1}{sup +1.4}(syst) ± 0.3(lumi) pb for a top quark mass of m{sub t} = 175 GeV/c2.



Measurement of the Cross Section for T Anti-t Production in P Anti-p Collisions Using the Kinematics of Lepton + Jets Events

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Page : 45 pages

File Size : 49,13 MB

Release : 2005

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The authors present a measurement of the top pair production cross section in p{bar p} collisions at √s = 1.96 TeV. We collect a data sample with an integrated luminosity of 194 ± 11 pb−1 with the CDF II detector at the Fermilab Tevatron. We use an artificial neural network technique to discriminate between top pair production and background processes in a sample of 519 lepton + jets events, which have one isolated energetic charged lepton, large missing transverse energy and at least three energetic jets. We measure the top pair production cross section to be [sigma]{sub t{bar t}} = 6.6 ± 1.1 ± 1.5 pb, where the first uncertainty is statistical and the second is systematic.