Measurement of Wγ and Zγ production in proton-proton collisions at √s =7 TeV with the ATLAS detector

We present studies of Wand Z bosonswith associated high energy photons produced in ppcollisions at √s=7 TeV. The analysis uses 35 pb^(−1) of data collected by the ATLAS experimentin 2010. The event selection requires Wand Z bosonsdecaying into high p T leptons(electrons or muons) and a photon with E_T > 15 GeV separated from the lepton(s) by a distance ∆R(l, γ) > 0.7 in η-ϕ space. A total of 95 (97) pp → e^±vγ + X( pp → μ^±vγ + X) and 25 (23) pp → e^+e^− γ + X( pp → μ^+μ^−γ + X) event candidates are selected. The kinematic distributions of the leptonsand photons and the production cross sections are measured. The data are found to agree with Standard Model predictions that include next-to-leading-order O(αα_s ) contributions.