S-matrix theory of final-state interactions

Some recent equations for final-state interactions based on the explicit insertion of unitarity singularities in an on-mass-shell analyticS-matrix theory are considered. Numerical solutions for the model case of spinless particles are given. This forms the framework for a discussion of the expected magnitudes of multiple-rescattering effects, which are of topical interest. The equations are straightforward numerically, and comparison of the results shows the features which are independent of the details of the individual theories.