Beyond leading order effects in photon pair production at the Tevatron
  We discuss effects induced by beyond leading order contributions to photon pair production. We point out that next to leading order contributions to the fragmentation component of the signal lead to a change in the shape of distributions. This is already mildly visible in present Tevatron data though stringent isolation criteria tend to suppress the fragmentation component considerably. We expect the effect to be experimentally confirmed in future data samples with higher statistics which would serve as a precision test for QCD. 
T. Binoth (1,2), J. Ph. Guillet (1), E. Pilon (1), M. Werlen (1),   ((1)LAPTH, Annecy, (2) University of Edinburgh)