Measurement of the top quark pair production cross section in the lepton+jets channel in proton-antiproton collisions at s=1.96TeV

We present a measurement of the inclusive top quark pair production cross section in pp¯ collisions at s=1.96TeV utilizing data corresponding to an integrated luminosity of 5.3fb^-1 collected with the D0 detector at the Fermilab Tevatron Collider. We consider final states containing one high-p_T isolated electron or muon and at least two jets, and we perform three analyses: one exploiting specific kinematic features of tt¯ events, the second using b-jet identification, and the third using both techniques to separate the tt¯ signal from the background. In the third case, we determine simultaneously the tt¯ cross section and the ratio of the production rates of W+heavy flavor jets and W+light flavor jets, which reduces the impact of the systematic uncertainties related to the background estimation. Assuming a top quark mass of 172.5 GeV, we obtain σ_tt¯=7.78_-0.64^+0.77pb. This result agrees with predictions of the standard model.