Angular distributions of preequilibrium reactions within a generalized exciton model

Abstract

The phase space used in the exciton model of preequilibrium reactions has been extended by including the total linear momentum of the exciton gas. The densities of exciton states with conserved total energy and momentum are estimated with the partition-function method in the saddle-point approximation. Introducing these quantities into the closed-form equations of the exciton model the angular distributions of nucleon induced preequilibrium reactions are calculated for various incident energies and target mass numbers. A normalizing factor is used to fit the absolute value of the differential cross section. The results are compared with experiment as well as with calculations following previous approaches to the description of preequilibrium angular distributions. The experimental data are reproduced to the same extent as within other attempts to calculate preequilibrium angular distributions.