Excitation spectra of exotic nuclei in a self-consistent phonon-coupling model

TL;DR

This paper investigates the excitation spectra of exotic Ni and Sn nuclei, emphasizing the impact of phonon coupling on spectral broadening and low-lying dipole strength, with implications for astrophysical processes.

Contribution

It introduces a self-consistent phonon-coupling model based on Skyrme-Hartree-Fock to analyze giant resonances and low-lying dipole strength in exotic nuclei.

Findings

Phonon coupling causes significant broadening of spectral distributions.

Low-lying dipole strength in neutron-rich nuclei is qualitatively altered.

Spectral broadening is especially pronounced in very neutron-rich isotopes.

Abstract

We explore giant resonance spectra and low-lying dipole strength in the Ni and Sn chains from proton rich to very neutron rich isotopes, relevant in astrophysical reaction chains. For the theoretical description we employ the random-phase approximation (RPA) plus many-body effects through a phonon coupling model with optimized selection of phonons. The nuclear force is based on the Skyrme-Hartree-Fock energy functional carried consistently through all steps of modelling. The main effect of phonon coupling is a broadening of the spectral distributions (collisional width). This broadening is particularly dramatic for low-lying dipole strength in very neutron rich nuclei delivering there a qualitative change of the spectra.