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.

Measurement of the W(+)W(-) Cross Section in root s=7 TeV pp Collisions with ATLAS RID F-6345-2010 RID E-5642-2011 RID G-8816-2011 RID F-2602-2010 RID F-7696-2011 RID C-5889-2009 RID G-5156-2010 RID E-6530-2011 RID G-6305-2011 RID F-7543-2011 RID B-2261-2010 RID F-3085-2011 RID B-6634-2009 RID G-1279-2010 RID B-4633-2010 RID G-1087-2011 RID A-3097-2011 RID F-1014-2011 RID B-6717-2011 RID A-6640-2010 RID C-9883-2009