Final-State Interaction in the Presence of Absorption

Abstract

There is by now a good agreement between the distorted-wave approximation and the sharpening of the peripheral peak by competing processes, although the theory itself has not been correctly derived at high energy. We show that the main result of the distorted-wave approximation can be derived by applying the dispersion theory of final-state interactions to the eigenstates of the $S$ matrix. Some assumptions about the mean values and the variation of the eigen-phase-shifts that fit with scattering experiment have to be made. The theory does not apply to low angular momenta. It is valid in nuclear physics.