NUCLEAR-DEPENDENCE IN DIRECT PHOTON PRODUCTION

We calculate the nuclear dependence of direct photon production in had ron-nucleus collisions. In terms of a multiple scattering picture, we factorize the cross section for direct photon production into calculab le short-distance partonic parts times multiparton correlation functio ns in nuclei. We present the hadron-nucleus cross section as A(alpha) times the hadron-nucleon cross section. Using information on the multi parton correlation functions extracted from photon-nucleus experiments , we compute the value of alpha as a function of transverse momentum o f the direct photon. We also compare our results with recent data from Fermilab experiment E706.