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

Journal of High Energy Physics 2011.10 (2011): 132 reproduced by permission of Scuola Internazionale Superiore di Studi Avanzati (SISSA)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) × ß(W → lν) = 10.31 ± 0.02 (stat.) ± 0.09 (syst.) ± 0.10 (th.) ± 0.41 (lumi.) nb and σ(pp → ZX) x 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 → ℓv))/(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+ν))/(σ(pp → W-X) × B(W- → ℓ-v̄)) = 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 function