Core-polarization effects on stretched particle-hole excitations in closed shell nuclei

Abstract
Configuration mixing calculations based on a first-order perturbation theory are carried out to study higher-shell mixing effects on the stretched 1ω particle-hole excitations. It is shown that the suppression of the transition strengths which has been observed in electron scattering and in hadronic reactions can be obtained theoretically in all the closed shell nuclei, being in qualitative agreement with experiments.