Pion nucleus potential from scattering data and a test of charge symmetry

A modified form of the inverse scattering method of Newton and Sabatier is applied to generate local complex potentials for the scattering of π± on zero spin and zero isospin nuclei. The phase shifts and inelasticity parameters, used as inputs, are extracted from a partial wave analysis of the elastic differential cross-section data by parametrizing the nuclear amplitude. Analytic mapping techniques are used to get a better accuracy in the phase shift analysis. The nuclear parts of the inversion potentials for π+ and π- scattering on 4He are compared as a possible test of charge symmetry breaking. The method has been repeated for several incident pion energies below the (3,3) resonance threshold. copyright 1997 The American Physical Society