Measurement of photon production at ATLAS

The production of prompt isolated photons at hadron colliders provides stringent tests of perturbative QCD and can be used to evaluate probability density functions of partons in the proton. In this talk, we present the measurements of the isolated-photon plus two jets and the inclusive isolated-photons cross sections, both measured using proton-proton collision data collected by the ATLAS experiment at Ãs=13 TeV. A ratio of photon cross sections at Ãs=8 and Ãs=13 TeV will also be presented. The results are compared with state-of-the-art theory predictions, indicating several interesting discrepancies.