Effects of ground-state correlations on damping of giant dipole resonaces in $LS$ closed shell nuclei

Abstract

The effects of ground-state correlations on the damping of isovector giant dipole resonances in $LS$ closed shell nuclei ${}^{16}$O and ${}^{40}$Ca are studied using extended random-phase-approximation (RPA) approaches derived from the time-dependent density-matrix theory. It is pointed out that unconventional two-body amplitudes of one particle--three hole and three particle--one hole types which are neglected in most extended RPA theories play an important role in the fragmentation of isovector dipole strength.

Comments: 4 pages, 4 figures. arXiv admin note: text overlap with arXiv:2009.02014, arXiv:1712.02006