The effect of the pion and $\Delta$ optical potentials on the propagation of the pion and delta in a semiclassical transport model of pion-nuclear reactions is studied. It is shown that the reaction and true absorption cross sections are increased to become closer to the measured cross sections. The derivative terms in the optical potential are shown to be particularly important. However, the distribution of final products produced still has some discrepancies compared to experiment, indicating that the mechanism for the deposition of the pion energy in the nucleus is not completely understood.

NUCLEAR REACTIONS The effect of optical potential on mean free paths in pion-nucleus reactions. Total reaction and absorption cross section calculated for pions incident on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$.

• Received 17 April 1979

DOI:https://doi.org/10.1103/PhysRevC.21.1056