Isobaric Multiplet Mass Equation within nuclear Density Functional Theory

TL;DR

This paper extends nuclear Density Functional Theory to include isospin-symmetry-breaking effects, systematically studying their impact on nuclear mass equations and comparing results with Green Function Monte Carlo calculations to understand the physical origins of these effects.

Contribution

It introduces proton-neutron mixing and ISB terms into DFT at NLO, providing a systematic analysis of IMME coefficients and their physical origins, with comparison to GFMC results.

Findings

ISB DFT and GFMC results agree reasonably well.

Both methods describe experimental data with similar accuracy.

Electromagnetic and nuclear ISB contributions are consistent, suggesting electromagnetic effects are not dominant.

Abstract

We extend the nuclear Density Functional Theory (DFT) by including proton-neutron mixing and contact isospin-symmetry-breaking (ISB) terms up to next-to-leading order (NLO). Within this formalism, we perform systematic study of the nuclear mirror and triple displacement energies, or equivalently of the Isobaric Multiplet Mass Equation (IMME) coefficients. By comparing results with those obtained within the existing Green Function Monte Carlo (GFMC) calculations, we address the fundamental question of the physical origin of the ISB effects. This we achieve by analyzing separate contributions to IMME coefficients coming from the electromagnetic and nuclear ISB terms. We show that the ISB DFT and GFMC results agree reasonably well, and that they describe experimental data with a comparable quality. Since the separate electromagnetic and nuclear ISB contributions also agree, we conclude that the beyond-mean-field electromagnetic effects may not play a dominant role in describing the ISB effects in finite nuclei.