Measurements of inclusive W and Z cross sections in pp collisions at $ \sqrt {s} = 7 $ TeV

Abstract

s = 7 TeV are presented, based on 2.9 pb -1 of data recorded by the CMS detector at the LHC. The measurements, performed in the electron and muon decay channels, are combined to give (pp WX) B(W ) = 9.95 0.07 (stat.) 0.28 (syst.) 1.09 (lumi.) nb and (pp ZX) B(Z + -) = 0.931 0.026 (stat.) 0.023 (syst.) 0.102 (lumi.) nb, where stands for either e or . Theoretical predictions, calculated at the next-to-next-to-leading order in QCD using recent parton distribution functions, are in agreement with the measured cross sections. Ratios of cross sections, which incur an experimental systematic uncertainty of less than 4%, are also reported.