Enhanced emissions of hard photons in heavy ion reactions by the particle correlation effect.

Abstract

This paper studies the particle correlation effect on hard photon production in heavy ion reactions at intermediate energies. It is indicated that this mechanism is able to increase the high-momentum component in nucleon distribution in phase space, and consequently increase the production of hard photons. A modified version of the Boltzmann-Uehling-Uhlenbeck equation by incorporation of the \ensuremath{\alpha}-like cluster effect has been developed. As examples, we studied, by using the new model, the photon productions in the reactions of $^{86}\mathrm{Kr}$ on $^{12}\mathrm{C}$, $^{\mathrm{nat}}\mathrm{Ag}$, and $^{197}\mathrm{Au}$ targets, respectively, at the same beam energy E/A=44 MeV. The results show that the incorporation of the cluster effect would lead to an enhancement of hard photon emission, especially at backward angles, and improve the agreement between the predicted and measured data. The mechanism underlying such enhancement has been explored.