Microscopic study of theΔ-nucleus potential from a many-body Hamiltonian forπ,N, andΔ

The strength of the $\Delta$-nucleus potential is calculated from the many-body Hamiltonian for $\pi$, $N$, and $\Delta$ constructed by Betz and Lee. The results are compared to the empirical values of the $\Delta$-hole doorway model. It is found that the calculated strength of the central potential reproduces the empirical one to a large extent. However, the calculated spin-orbit potential is much smaller than that of of the $\Delta$-hole model. It is also shown that the pion absorption through the $N\Delta S$ wave only accounts for about half of the total absorption. The sums of other $N\Delta$ partial waves are found to be equally important.