Measurement of the inclusive W and Z production cross sections in pp collisions at √s = 7 TeV with the CMS experiment

Abstract

A measurement of inclusive W and Z production cross sections in pp collisions at √s = 7TeV is presented. The electron and muon decay channels are analyzed in a data sample collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 36 pb^-1. The measured inclusive cross sections are σ(pp → WX) × B(W → lυ) = 10.31 ± 0.02 (stat:) ± 0.09 (syst:) ± 0.10 (th:) ± 0.41 (lumi:) nb and σ(pp → ZX) × B(Z → l⁺l^-) = 0.974 ± 0.007 (stat:) ± 0.007 (syst:) ± 0.018 (th:) ± 0.039 (lumi:) nb, limited to the dilepton invariant mass range 60 to 120 GeV. The luminosity-independent cross section ratios are (σ(pp → WX) × B(W → lυ)) / (σ(pp → ZX) × B(Z →l⁺l^-) = 10.54 ± 0.07 (stat:) ± 0.08 (syst:) ± 0.16 (th:) and (σ(pp → W⁺X) × B(W⁺→l⁺υ)) / (σ(pp → W⁺X) × B(W^-→l^-υ)) = 1.421±0.006 (stat:)±0.014 (syst:)±0.029 (th:). The measured values agree with next-to-next-to-leading order QCD cross section calculations based on recent parton distribution functions.