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

We provide the first measurement of the WW production cross section in pp collisions at √s =7 TeV. The WW leptonic decay channels are analyzed with data corresponding to 35 pb^−1 of integrated luminosity collected by the ATLAS detector during 2010 at the CERN Large Hadron Collider. With eight observed WW candidate events and an estimated background of 1.7±0.6, the measured WW production cross section is 40+20/-16(stat)±7(syst) pb. The probability for the estimated background to fluctuate up to at least the observed number of events is 1.4×10^-3, corresponding to a signal significance of 3.0 standard deviations.