The structure of events triggered by direct photons in π−p, π+p andpp collisions at 280 GeV/c

The structure of events associated with the production of direct photons in π−p, π+p andpp reactions of 280 GeV/c has been studied using data from the WA 70 experiment at the CERN SPS. Results are presented on the distributions of the fractional momenta of the colliding partons and on the fragmentation of the recoil jet and a comparison is made with predictions using the structure functions of Duke and Owens in the Lund Monte Carlo with string fragmentation.