Nuclear structure and pion reactions

Shell model analyses of inelastic pion and electron scattering are used to derive many body wave functions suitable for DCX studies of masses 14 and 18. These calculations show clear evidence for the need to include core-excitations in the wave functions of the ground and excited states of these nuclei. The appropriate enhancement and quenching of the isoscalar and isovector one-body density matrix elements are deduced, and their possible effects on DCX cross-sections discussed. Effective (q-dependent) transitions, obtained from microscopic core-polarization calculations, are found to give an excellent description of the pion angular distributions and {pi}{sup {plus}}/{pi}{sup {minus}} ratios in this mass region, justifying the use of effective charges in shell model studies of pion reactions. 13 refs., 12 figs