Diphoton production at hadron colliders: a fully-differential QCD   calculation at NNLO
  We consider direct diphoton production in hadron collisions, and we compute the next-to-next-to-leading order (NNLO) QCD radiative corrections at the fully-differential level. Our calculation uses the $q_T$ subtraction formalism and it is implemented in a parton level Monte Carlo program. The program allows the user to apply arbitrary kinematical cuts on the final-state photons and the associated jet activity, and to compute the corresponding distributions in the form of bin histograms. We present selected numerical results related to Higgs boson searches at the LHC and corresponding results at the Tevatron. 
Stefano Catani, Leandro Cieri, Daniel de Florian, Giancarlo Ferrera   and Massimiliano Grazzini
hep-ph