A self-consistent study of multipole response in neutron-rich nuclei using a modified realistic potential

TL;DR

This study investigates the multipole responses of neutron-rich O and Sn isotopes using a modified realistic potential within self-consistent theoretical frameworks, analyzing effects of Hamiltonian corrections and comparing with experimental data.

Contribution

It introduces a modified realistic potential for self-consistent calculations of multipole responses in neutron-rich nuclei, including effects of center of mass and particle number violations.

Findings

Differences between Tamm-Dancoff and RPA approaches are quantitatively analyzed.

The impact of phenomenological corrections on energies and responses is discussed.

Comparison with experimental spectra clarifies the models' validity.

Abstract

The multipole response of neutron rich O and Sn isotopes is computed in Tamm-Dancoff and random-phase approximations using the canonical Hartree-Fock-Bogoliubov quasi-particle basis. The calculations are performed using an intrinsic Hamiltonian composed of a $V_{lowk}$ potential, deduced from the CD-Bonn nucleon-nucleon interaction, corrected with phenomenological density dependent and spin-orbit terms. The effect of these two pieces on energies and multipole responses is discussed. The problem of removing the spurious admixtures induced by the center of mass motion and by the violation of the number of particles is investigated. The differences between the two theoretical approaches are discussed quantitatively. Attention is then focused on the dipole strength distribution, including the low-lying transitions associated to the pygmy resonance. Monopole and quadrupole responses are also briefly investigated. A detailed comparison with the available experimental spectra contributes to clarify the extent of validity of the two self-consistent approaches.