Measurements of inclusive W and Z cross sections in pp collisions at √s=7  TeV

Measurements of inclusive W and Z boson production cross sections in pp collisions at 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 σ(pp→WX)×B(W→ℓν)=9.95±0.07(stat.)±0.28(syst.)±1.09 (lumi.) nb and σ(pp→ZX)×B(Z→ℓ+ℓ−)=0.931±0.026(stat.)±0.023(syst.)±0.102 (lumi.) nb, where ℓ stands for either e or μ. 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.ISSN:1126-6708ISSN:1029-847