Nuclear scattering of low energy pions

Abstract

We have estimated the parameters of the optical potential for low energy pion-nucleus scattering from the values obtained empirically in the analysis of pionic atom data. The ambiguities in these parameters are discussed. The shape of the low energy elastic scattering cross section for light elements is particularly sensitive to the relative strength of the repulsive and velocity-dependent attractive parts of the optical potential, and is well reproduced by pionic atom parameters. Absorption is the dominant reaction channel at low energies. Pion nucleon phase shifts are used to extrapolate optical model parameters to higher energies. The behavior of the elastic and inelastic angular distributions and of various partial cross sections is discussed, and compared with experiment.