First measurements of the W &#8594; &#8467;&#957; and Z/&#947; * &#8594; &#8467;&#8467; (&#8467; = e, &#956;) production cross sections in proton-proton collisions at are presented using data recorded by the ATLAS experiment at the LHC. The results are based on 2250 W &#8594; &#8467;&#957; and 179 Z/&#947; * &#8594; &#8467;&#8467; candidate events selected from a data set corresponding to an integrated luminosity of approximately 320 nb. The measured total W and Z/&#947; &#8727;-boson production cross sections times the respective leptonic branching ratios for the combined electron and muon channels are . BR(W &#8594; &#8467;&#957;) = 9.96 ± 0.23(stat) ± 0.50(syst) ± 1.10(lumi) nb and BR(Z/&#947; &#8727; &#8594; &#8467;&#8467;) = 0.82 ± 0.06 (stat) ± 0.05 (syst) ± 0.09(lumi) nb (within the invariant mass window 66 < m &#8467;&#8467; &lt; 116GeV). 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 &#8722; 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.

Measurement of the W -> lnu and Z/gamma* -> ll production cross sections in proton-proton collisions at √s = 7 TeV with the ATLAS detector

BERTIN, ANTONIO;BINDI, MARCELLO;CAFORIO, DAVIDE;DE CASTRO, STEFANO;DI SIPIO, RICCARDO;FABBRI, LAURA;