Measurement of the tt¯ production cross section in pp¯ collisions at s=1.96TeV using lepton+jets events with jet probability b-tagging

We present a measurement of the tt¯ production cross section using events with one charged lepton and jets from pp¯ collisions at a center-of-mass energy of 1.96 TeV. A b-tagging algorithm based on the probability of displaced tracks coming from the event interaction vertex is applied to identify b quarks from top decay. Using 318pb^-1 of data collected with the CDF II detector, we measure the tt¯ production cross section in events with at least one restrictive (tight) b-tagged jet and obtain 8.9_-1.0^+1.0(stat)_-1.0^+1.1(syst)pb. The cross section value assumes a top quark mass of m_t=178GeV/c² in the acceptance corrections. The dependence of the cross section on m_t is presented in the paper. This result is consistent with other CDF measurements of the tt¯ cross section using different samples and analysis techniques, and has similar systematic uncertainties. We have also performed consistency checks by using the b-tagging probability function to vary the signal-to-background ratio and also using events that have at least two b-tagged jets.