Diphoton production at hadron colliders in NNLO QCD

We consider higher-order QCD corrections for direct photon pair production in hadron collisions and we present results for the next-to-next-to-leading order (NNLO) calculation at fully differential level. The calculation is based on the qT -subtraction formalism and it is implemented in a parton level Monte Carlo numerical program. The program allows the user to apply arbitrary infrared-safe kinematical cuts on the final-state photons and on the accompaining jet activity. We show some illustrative numerical results at the LHC and the Tevatron.