Isospin mixing in nuclei within the nuclear density functional theory

TL;DR

This paper develops a self-consistent nuclear density functional method to analyze isospin mixing, effectively eliminating unphysical violations and exploring their dependence on nuclear parameters, with implications for beta decay corrections.

Contribution

It introduces a non-perturbative, self-consistent approach to quantify isospin mixing and corrects for mean-field violations in nuclear density functional theory.

Findings

Largest isospin-breaking effects in N=Z nuclei

Isospin violation decreases with neutron excess

Correlation between isospin mixing and proton-neutron radius difference

Abstract

We present the self-consistent, non-perturbative analysis of isospin mixing using the nuclear density functional approach and the rediagonalization of the Coulomb interaction in the good-isospin basis. The largest isospin-breaking effects are predicted for N = Z nuclei and they quickly fall with the neutron excess. The unphysical isospin violation on the mean-field level, caused by the neutron excess, is eliminated by the proposed method. We find a significant dependence of the magnitude of isospin breaking on the parametrization of the nuclear interaction term. A rough correlation has been found between the isospin mixing parameter and the difference of proton and neutron rms radii. The theoretical framework described in this study is well suited to describe a variety of phenomena associated with isospin violation in nuclei, in particular the isospin symmetry-breaking corrections to superallowed Fermi beta decays.