Measurement of the tt̄ production cross section in pp collisions at √s=7 TeV using the kinematic properties of events with leptons and jets

A measurement of the t t production cross section in proton-proton collisions at a centre-of-mass energy of 7 TeV has been performed at the LHC with the CMS detector. The analysis uses a data sample corresponding to an integrated luminosity of 36 pb -1 and is based on the reconstruction of the final state with one isolated, high transversemomentum electron or muon and three or more hadronic jets. The kinematic properties of the events are used to separate the t t signal from W+jets and QCD multijet background events. The measured cross section is 173 +39 -32 (stat.+ syst.) pb, consistent with standard model expectations.