Measurement of the t(t)over-bar production cross section in pp collisions at 7 TeV in lepton plus jets events using b-quark jet identification

A new measurement of the inclusive production cross section for pp -> t (t) over bar is performed at a center-of-mass energy of 7 TeV using data collected by the CMS experiment at the LHC. The analysis uses a data sample corresponding to an integrated luminosity of 36 pb(-1), and is based on the final state with one isolated, high transverse momentum muon or electron, missing transverse energy, and hadronic jets. The t (t) over bar content of the selected events is enhanced by requiring the presence of at least one jet consistent with b-quark hadronization. The measured cross section is 150 +/- 9(stat) +/- 17(syst) +/- 6(lumi) pb and is in agreement with higher-order QCD calculations. The combination of this measurement with a previous CMS result based on dileptons gives 154 +/- 17(stat + syst) +/- 6(lumi) pb.