A statistical model has been developed to compute total pion production cross sections at energies below the energy threshold for pion production in free nucleon-nucleon collisions. The model assumes that during a collision between two nuclei a fraction of their energy is released within an interaction volume and is rapidly distributed among the different degrees of freedom. The calculation of the probability of creating a pion is based on the statistical weights of the various possibilities. The model has been applied successfully to reactions between ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$, and ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ projectiles and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$, ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$, W, and U targets for energies ranging from 25 to 84 MeV/nucleon.

• Received 18 July 1988

DOI:https://doi.org/10.1103/PhysRevC.38.2964