Abstract: A measurement of inclusive W and Z production cross sections in pp collisions at ?s = 7 TeV 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 ?(pp ? WX) × B(W ?`?) = 10.31 ± 0.02 (stat.) ± 0.09 (syst.) ± 0.10 (th.) ± 0.41 (lumi.) nb and ?(pp ? ZX) × B(Z ? `+`?) = 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 (?(pp ? WX) × B(W ? `?)) / (?(pp ? ZX) × B(Z ? `+`?)) =10.54 ± 0.07 (stat.) ± 0.08 (syst.) ± 0.16 (th.) and (?(pp ? W+X) × B(W+ ? `+?)) /(?(pp ? W?X) × B(W? ? ??¯)) = 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.

Autoría

Descargar referencia