Resonating-group study of the N + 40Ca system

Abstract

The scattering of nucleons by 40Ca is studied with the resonating-group method. The 40Ca wave function used is a translationally invariant antisymmetrized product of single-particle wave functions of (1s)4(1p)12(1d)20(2s)4 configuration in a harmonic-oscillator well having an appropriately chosen width parameter. The nonlocal interaction between the nucleon and the 40Ca cluster is computed with the help of a generator-coordinate technique. Calculated results are compared with experimental data on bound states in 41Ca, as well as n + 40Ca and p + 40Ca differential cross-section and polarization data at various energies. In each of these comparisons, it is found that our results are generally quite satisfactory; in fact, the fits to experimental data on cross sections and polarizations are of similar quality as those obtained by conventional optical-model analyses which employ a large number of adjustable parameters. The importance of the Pauli principle is also examined in detail. Here we find that, at relatively high energies, the knockout exchange term is quite significant, but the heavy-particle pickup exchange term has a rather minor contribution.