Measurement of ttbar Pair Production Cross Section at sqrt(s)=7 TeV using b-quark Jet Identification Techniques in Lepton + Jet Events

An updated measurement of the production cross section for $pp \to t\bar{t}$ at a center-of-mass energy of 7 TeV using data collected by the CMS detector at the Large Hadron Collider is presented. The analysis uses data corresponding to an integrated luminosity between 0.8 and 1.1 fb$^{-1}$ using events with one isolated, high transverse momentum muon or electron, large missing transverse energy and hadronic jets. The \ttbar content of the data has been enhanced by requiring the presence of at least one jet consistent with originating from a $b$-quark. The cross section is extracted with a profile likelihood method using a fit to the number of reconstructed jets, the number of $b$-tagged jets, and the secondary vertex mass distribution. The measured cross section is $164.4 \pm 2.8 {\rm~(stat.)} \pm 11.9 {\rm~(syst.)} \pm 7.4 {\rm~(lum.)} \,\rm{pb}$ and is consistent with higher order QCD calculations. We perform a cross check analysis, which compares favorably to the main result.