Nonperturbative Calculation of Nuclear Matrix Elements from Two-Nucleon Phase Shifts

A method is presented for calculating two-body shell-model interaction matrix elements from scattering phase shifts, which applies to shifts of any magnitude and to tensor coupling. It is assumed that the average (shell-model) potential, expressed in two-nucleon relative coordinates, is slowly varying within the range of the free two-nucleon interaction. Examples are given for the $p$ shell and compared with the results of other methods, some of which include Pauli corrections.