This Letter presents a measurement of the W+W- production cross section in root s = 7 TeV pp collisions by the ATLAS experiment, using 34 pb(-1) of integrated luminosity produced by the Large Hadron Collider at CERN. Selecting events with two isolated leptons, each either an electron or a muon, 8 candidate events are observed with an expected background of 1.7 +/- 0.6 events. The measured cross section is 41(-16)(+20)(stat) +/- 5(syst) +/- 1(lumi) pb, which is consistent with the standard model prediction of 44 +/- 3 pb calculated at next-to-leading order in QCD.
Aad, G., Abbott, B., Abdallah, J., Abdelalim, A.a., Abdesselam, A., Abdinov, O., et al. (2011). Measurement of the W+W- Cross Section in root s=7 TeV pp Collisions with ATLAS. PHYSICAL REVIEW LETTERS, 107(4), 1-18 [10.1103/PhysRevLett.107.041802].