Measurement of the t t production cross section in pp collisions at 7 TeV in leptonþ jets events using b-quark jet identification

S. Chatrchyan et al.* (CMS Collaboration) (Received 17 August 2011; published 14 November 2011) A new measurement of the inclusive production cross section for pp ! t t is performed at a center-ofmass 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 , 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 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 9ðstatÞ 17ðsystÞ 6ðlumiÞ 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 17ðstatþ systÞ 6ðlumiÞ pb.