Measurement of the t t-bar Production Cross Section in pp Collisions at 7 TeV in Lepton + Jets Events Using b-quark Jet Identification

TL;DR

This paper reports a measurement of the top-antitop quark pair production cross section at 7 TeV in proton-proton collisions, using lepton+jets events with b-jet identification, consistent with QCD predictions.

Contribution

First measurement of ttbar production cross section at 7 TeV using b-jet tagging in lepton+jets channel with CMS data.

Findings

Measured cross section: 150 pb with uncertainties.

Combined CMS result: 154 pb with uncertainties.

Results agree with higher-order QCD calculations.

Abstract

A new measurement of the inclusive production cross section for pp to t t-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 inverse picobarns, and is based on the final state with one isolated, high transverse momentum muon or electron, missing transverse energy, and hadronic jets. The ttbar 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.