Measurement of the T Tbar Cross Section at the Run II Tevatron Using Support Vector Machines
Measurement of the T Tbar Cross Section at the Run II Tevatron Using Support Vector Machines

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Published: 2010

Total Pages: 419

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This dissertation measures the t{bar t} production cross section at the Run II CDF detector using data from early 2001 through March 2007. The Tevatron at Fermilab is a p{bar p} collider with center of mass energy √s = 1.96 TeV. This data composes a sample with a time-integrated luminosity measured at 2.2 ± 0.1 fb−1. A system of learning machines is developed to recognize t{bar t} events in the 'lepton plus jets' decay channel. Support Vector Machines are described, and their ability to cope with a multi-class discrimination problem is provided. The t{bar t} production cross section is then measured in this framework, and found to be [sigma]{sub t{bar t}} = 7.14 ± 0.25 (stat){sub -0.86}{sup +0.61}(sys) pb.

Measurement of the T[bar T] Production Cross Section at the Tevatron
Measurement of the T[bar T] Production Cross Section at the Tevatron

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Published: 2003

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We report on the measurement of the t[anti t] production cross section obtained by CDF and D0 experiments with p[anti p] collisions at[radical]s=1. 8 TeV. The analyses presented here refer to[integral] Ldt[approx]11O pb[sup -1] collected at the Fermilab Tevatron collider during the run 1992-96. About 85% of the possible t[anti t] decays have been studied in different channels classified according to the number of high P[sub T] leptons found in the final state. The production cross section has been measured in each individual channel and then combined into a single value for each experiment, which is[sigma][sub tt]= 7.5[sup 1.9][sub 1.6] pb for CDF and[sigma][sub tt]= 5.77[+-] 1.76 pb for D0.

Measurement of the T Tbar Production Cross Section at
Measurement of the T Tbar Production Cross Section at

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Published: 2001

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We report on the results from the analyses of[ital t][ital[anti t]] decays in[ital dilepton] and[ital lepton+jets] modes with[approx]100 pb[sup -1] of[ital p][ital[anti p]] Collider data at[radical]s= 1.8 TeV collected by the D[null] experiment at the Fermilab Tevatron. We have observed 37[ital t][ital[anti t]] candidate events while the estimated background is 13.4[+-] 3.0 events. The[ital t][ital[anti t]] production cross section has been measured to be 5.2[+-] 1.8 pb at a top quark mass of 170 GeV/c[sup 2].

Measurement of the Ttbar Production Cross Section at S**(1/2)
Measurement of the Ttbar Production Cross Section at S**(1/2)

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Published: 2005

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A measurement of the t[bar t] production cross section in the lepton+jets channels with the D0 detector at [radical]s = 1.96 TeV using the lifetime-tagging techniques is presented. The t[bar t] cross section is estimated from the combination of the e+jets and [mu]+jets channels. The obtained result [sigma][sub tt][sup -] = 7.47 [sub -1.14][sup +1.22](stat)[sub -1.03][sup +1.65](syst) [+-] 0.49 (lumi) pb is consistent with the Standard Model expectation.

Measurement of the T Anti-t Production Cross-section at S**ư
Measurement of the T Anti-t Production Cross-section at S**ư

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Published: 2006

Total Pages: 4

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A measurement of the t{bar t} production cross section at √s = 1.96 TeV in the dilepton final states using a lepton+track selection and secondary vertex b-tagging is presented. One of the two leptons from the decay of the t{bar t} pair is allowed to be identified only as an isolated track to improve the selection efficiency. The result is combined with a measurement in the t{bar t} → e? final state. The measurements are based on 370 pb−1 of data collected with the D0 experiment at the Tevatron collider. The preliminary cross section obtained in the combined lepton+track and e? channel is:?{sub t{bar t}} = 8.6{sub -1.7}{sup +1.9}(stat) ± 1.1(syst) ± 0.6(lumi) pb.

Measurement of the Ttbar Production Cross Section in the All-jets Final State in Pp Collisions at $\sqrt{s}$
Measurement of the Ttbar Production Cross Section in the All-jets Final State in Pp Collisions at $\sqrt{s}$

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Published: 2015

Total Pages: 34

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The cross section for tt production in the all-jets final state is measured in pp collisions at a centre-of-mass energy of 8 TeV at the LHC with the CMS detector, in data corresponding to an integrated luminosity of 18.4 fb-1. The inclusive cross section is found to be 275.6 ±6.1 (stat) ± 37.8 (syst) ± 7.2 (lumi) pb. The normalized differential cross sections are measured as a function of the top quark transverse momenta, pT, and compared to predictions from quantum chromodynamics. The results are reported at detector, parton, and particle levels. In all cases, the measured top quark pT spectra are significantly softer than theoretical predictions.