A calculation of pion absorption cross sections

Pion absorption cross sections on nuclei are calculated from an optical potential, taking account of absorption after several quasi-free processes. The imaginary part of the optical potential is assumed to consist of quasi-free and absorption terms, which are used to estimate the probabilities of a pion to escape from the nucleus after quasi-free processes, to repeat a quasi-free process and to be absorbed. Inelastic, single-charge exchange and double-charge exchange cross sections are also calculated by further dividing the quasi-free term into inelastic and charge-exchange parts. (orig.)