Parametrization of pion-nucleon phase shifts and effects upon pion-nucleus scattering calculations

Pi meson interactions with free nucleons as known from recent experiments have been fit by Arndt et al. in the form of phase shifts. In the present work these phase shifts are fit by a simple parametrization, and observables computed from the resulting parametrized phase shifts are compared successfully to important examples of recent measurements. The parameters of this work are readily suited to pion-nucleus optical model codes built upon the impulse approximation. Some examples of the effect of the new pion-nucleon data upon these pion-nucleus calculations are shown, relative to older results based upon far fewer pion-nucleon data.