ANALYSIS OF HARD 2-PHOTON CORRELATIONS MEASURED IN HEAVY-ION REACTIONS AT INTERMEDIATE ENERGIES

Recently reported measurements of hard photon correlations in the reac tions Ar-36 on Al-27 at 95A MeV, Kr-86 on Ni-nat at 60A MeV, and Ta-18 1 on Au-197 at 39.5A MeV are analyzed. A Boltzmann-Uhling-Uhlenbeck tr ansport model is used to describe the photon production by individual nucleon-nucleon collisions. In the lighter systems we find the best ag reement with data when taking into account only photons from first-cha nce collisions of nucleons or photons produced during the passage of t he nuclei, while the model predicts also a considerable late-time emis sion of photons, which leads to a depletion of the calculated correlat ion function. The accuracy of the present data does not allow firm con clusions on the reliability of this late-time evolution. Our investiga tions do not support a recently reported interference pattern in the h eavy Ta + Au system.