Microscopic study of D-nucleus dynamics

The purpose of this work is to explore the dynamical origin of the Δ-nucleus interaction which has been treated phenomenologically in the study of intermediate energy pion nucleus scattering. In the one-hole-line approximation the Δ-nucleus potential can be calculated from the NΔ G matrix by imposing the Bruckner-Hartree-Fock self-consistent condition. The authors first calculation was done in 1982, by using the separable model Hamiltonian of Betz and Lee. Extensive calculations with their newly developed meson-exchange theory have been performed recently. It is found that the calculated absorptive part of the Δ-nucleus potential is much less than the phenomenological value, ranging from only 20% (from the Bonn potential) to about 60% (from the Paris potential) of phenomenological values. These results suggest that more than one nucleon in a nuclear medium are active in annihilating the incoming pion