Book Description

Data are presented on pion-nucleus double-charge-exchange scattering at energies between 300 and 500 MeV, the highest energies measured so far, together with a review of results at lower energies. The small-angle excitation functions disagree with predictions based on a six-quark cluster model and on an optical model consistent with single-charge-exchange scattering at these energies, but they are consistent with a distorted-wave calculation. Data on f--2-shell nuclei are in partial agreement with a two-amplitude model which is successful at lower energies. In order to achieve good understanding of this process at these energies, more work, both experimental and theoretical, is needed. 16 refs., 6 figs.