Constraints on $q\bar q \gamma\gamma$ Contact Interactions at Future   Hadron Colliders
  We explore the capability of the Tevatron and LHC as well as other future hadron colliders to place limits on the possible existence of flavor-independent $q \bar q \gamma\gamma$ contact interactions which can lead to an excess of high $p_t$ diphoton events with large invariant masses. Constraints on the corresponding $e^+e^-\gamma\gamma$ contact interaction already exist from LEP. In the case of hadron colliders, strong constraints on the scale associated with such interactions are achievable in all cases, e.g., of order 0.9(3) TeV at TeV33(LHC). [To appear in the Proceedings of the 1996 DPF/DPB Summer Study on New Directions for High Energy Physics-Snowmass96, Snowmass, CO, 25 June-12 July, 1996.] 
Thomas G. Rizzo