We calculate prompt photon production in high-energy nuclear collisions. We focus on the broadening of the intrinsic transverse momenta of the partons in the initial state from nuclear effects, and their influence on the prompt photon p1 distribution. Comparing to WA98 data from Pb-Pb collisions at √s=17.4A GeV we find evidence for the presence of nuclear broadening at high p1 in this hard process. Below p1∼2.7 GeV the photon distribution is due to small momentum transfer processes. At RHIC energy, √s=200A GeV, the effect of intrinsic transverse momentum on the spectrum of prompt photons is less prominent. The region p1=3-4 GeV would be the most promising for studying the nuclear broadening effects at that energy. Below p1=2-3 GeV the contribution from large momentum transfer flattens out, and we expect that region to be dominated by soft contributions.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics