Abstract

The production of prompt isolated photons at hadron colliders provides a stringent test of perturbative QCD and can be used to probe the proton structure with a hard colourless probe less affected by hadronisation effects than jet production. Furthermore, searches for new physics in final states involving photons, despite the relatively small cross-section compared to hadronic signatures, provide a powerful handle in the signal over background discrimination. Such searches find their motivation in a wide panorama of theoretical models such as minimal extensions of the Standard Model, extra dimensions and dark matter. Over the past years the ATLAS collaboration has developed and optimised a set of photon reconstruction and identification techniques in order to reach the detectors design performance. Such techniques are described in this talk. A summary of recent Standard Model measurements is shown and promising results on searches for new physics involving photons are presented.