Measurement of the Top Quark Pair Production Cross Section in p-p Collisions at √ s=7 TeV in the l+ τ Channel with ATLAS

The measurement of the cross section of top quark pair production in proton-proton collisions at a center-of-mass energy of 7 TeV recorded with the ATLAS detector at the LHC is reported. The data sample used corresponds to an integrated luminosity of 2.05 fb-1. Events with an isolated electron or muon and a tau lepton decaying hadronically are used. In addition, a large missing transverse momentum and two or more energetic jets are required. At least one of the jets must be identified as originating from a b-quark. The measured cross section, 178 ± 12 stat. ± 18 sys. ± 7 lumi. pb is in good agreement with the Standard Model prediction.