Multireference covariant density-functional theory for the low-lying states of odd-mass nuclei

TL;DR

This paper extends multireference covariant density-functional theory to accurately describe low-lying states of odd-mass nuclei, incorporating quadrupole-octupole deformations and symmetry projections, demonstrated on magnesium and neon isotopes.

Contribution

The work introduces a novel MR-CDFT approach for odd-mass nuclei that includes octupole correlations and symmetry projections, improving the description of low-energy nuclear states.

Findings

Successfully reproduces low-energy spectra of $^{25}$Mg.

Illustrates octupole correlation effects in $^{21}$Ne.

Demonstrates MR-CDFT's effectiveness for odd-mass nuclei.

Abstract

We extend multireference covariant density-functional theory (MR-CDFT) based on a relativistic point-coupling energy functional to describe the low-lying states of odd-mass nuclei. The nuclear wave function is constructed as a superposition of quadrupole-octupole deformed mean-field configurations, with projection onto angular momentum, particle numbers, and parity within the framework of the generator coordinate method. Using $^{25}$Mg as an example, we calculate the energy spectrum, electric multipole, and magnetic dipole transition strengths based on three different schemes for the mean-field configurations of odd-mass nuclei. We find that the low-energy structure of $^{25}$Mg is reasonably reproduced in all three schemes. In particular, the effect of octupole correlation is illustrated in the application to the low-lying parity doublets of $^{21}$Ne. This work demonstrates the success of the MR-CDFT for the low-lying states of odd-mass nuclei with possible strong quadruple-octupole correlations.