First measurements of the W → lν and Z/γ* → ll (l = e, μ) production cross sections in proton-proton collisions at √s = 7 TeV are presented using data recorded by the ATLAS experiment at the LHC. The results are based on 2250 W → lν and 179 Z/γ* → ll candidate events selected from a data set corresponding to an integrated luminosity of approximately 320 nb-1. The measured total W and Z/γ*-boson production cross sections times the respective leptonic branching ratios for the combined electron and muon channels are σtot(W) * BR(W → lν) = 9.96 ± 0.23(stat) ± 0.50(syst) ± 1.10(lumi) nb and σtot(Z/γ*) * BR(Z/γ* → ll) = 0.82 ± 0.06(stat) ± 0.05(syst) ± 0.09(lumi) nb (within the invariant mass window 66 < mll < 116 GeV). The W/Z cross-section ratio is measured to be 11.7 ± 0.9(stat) ± 0.4(syst). In addition, measurements of the W+ and W- production cross sections and of the lepton charge asymmetry are reported. Theoretical predictions based on NNLO QCD calculations are found to agree with the measurements.
|Journal||Journal of High Energy Physics|
|Publication status||Published - 2010|