Measurement of the t(t)over bar production cross section in p(p)over bar collisions at root s=1.96 TeV using lepton plus jets events with semileptonic B decays to muons

We present a measurement of the t (t) over bar production cross section using 194 pb(-1) of CDF II data using events with a high transverse momentum electron or muon, three or more jets, and missing transverse energy. The measurement assumes 100% t -> Wb branching fraction. Events consistent with t (t) over bar decay are found by identifying jets containing heavy-flavor semileptonic decays to muons. The dominant backgrounds are evaluated directly from the data. Based on 20 candidate events and an expected background of 9.5 +/- 1.1 events, we measure a production cross section of 5.3 +/- 3.3(-1.0)(+1.3) pb, in agreement with the standard model.