Measurements of the cross sections for the inclusive productions of isolated prompt photons and di-photons in proton-proton collisions at a centre-of-mass energy √ s = 7 TeV at the Large Hadron Collider (LHC) with the ATLAS detector are presented. Photon candidates are identified by combining information from the calorimeters and from the inner tracker. Residual background in the selected sample is estimated from data based on the observed distribution of the transverse isolation energy in a narrow cone around the photon candidate. The results are compared to predictions from next-to-leading order perturbative QCD calculations.

In the light of the new prompt photon data collected by PHENIX at RHIC and by D∅ at the run II of the Tevatron, we revisit the world prompt photon data, both inclusive and isolated, in hadronic collisions, and compare them with the NLO QCD calculations implemented in the Monte Carlo programme JETPHOX.