We present measurements of the top-antitop production cross section in b-tagged lepton + jets events from proton-antiproton collisions at 1.96 TeV using the CDF detector at Fermilab. B-jets are tagged with either a secondary vertex algorithm, or a soft lepton tagger that identifies muons from B hadron semileptonic decays. With Tevatron Run II data, we estimate the top-antitop signal fraction in two different ways: by estimating the various background contributions, and by fitting directly the leading jet transverse energy spectrum for the signal and background contributions. A subset of the sample with two secondary vertex tagged jets yields a production cross section consistent with the inclusive measurements. Results are consistent with a Standard Model top-antitop signal and current measurements of the top quark mass.

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 √s=1. 8 TeV. The analyses presented here refer to ∫ Ldt ≈11O pb−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.

A measurement of the t{bar t} production cross section at {radical}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} {yields} e{mu} final state. The measurements are based on 370 pb{sup -1} of data collected with the D0 experiment at the Tevatron collider. The preliminary cross section obtained in the combined lepton+track and e{mu} channel is: {sigma}{sub t{bar t}} = 8.6{sub -1.7}{sup +1.9}(stat) {+-} 1.1(syst) {+-} 0.6(lumi) pb.

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.

We measure the production cross section of t{bar t} events in p{bar p} collisions at √s = 1.96 TeV. The data was collected by the CDF experiment in Run 2 of the Tevatron accelerator at the Fermi National Accelerator Laboratory between 2002 and 2007. 1.7 fb−1 of data was recorded during this time period. We reconstruct t{bar t} events in the lepton+jets channel, whereby one W boson - resulting from the decay of the top quark pairs - decays leptonically and the other hadronically. The dominant background to this process is the production of W bosons in association with multiple jets. To distinguish t{bar t} from background, we identify soft electrons from the semileptonic decay of heavy flavor jets produced in t{bar t} events. We measure a cross section of [sigma]{sub p{bar p}} = 7.8 ± 2.4(stat) ± 1.6(syst) ± 0.5(lumi).

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