Measurement of the W+W− production cross section in proton-proton collisions at √s = 7 TeV with the ATLAS detector

We report a measurement of the W+W− production cross section in pp collisions at sqrt(s) = 7 TeV. The W+W− leptonic decay channels are analyzed using data corresponding to 1.02 fb−1 of integrated luminosity collected by the ATLAS detector during 2011 at the CERN Large Hadron Collider. With 414 observed W+W− candidate events and an estimated background of 170±28 events, the measured W+W− production cross section is 48.2 ± 4.0(stat) ± 6.4(syst) ± 1.8(lumi) pb, in agreement with the Standard Model NLO prediction of 46±3 pb.