PION-NUCLEUS POTENTIAL FROM SCATTERING DATA AND A TEST OF CHARGE-SYMMETRY

A modified form of the inverse scattering method of Newton and Sabatie r is applied to generate local complex potentials for the scattering o f pi(+/-) on zero spin and zero isospin nuclei. The phase shifts and i nelasticity parameters, used as inputs, are extracted from a partial w ave analysis of the elastic differential cross-section data by paramet rizing the nuclear amplitude. Analytic mapping techniques are used to get a better accuracy in the phase shift analysis. The nuclear parts o f the inversion potentials for pi(+) and pi(-) scattering on He-4 are compared as a possible test of charge symmetry breaking. The method ha s been repeated for several incident pion energies below the (3,3) res onance threshold.