Spin-orbit and tensor mean-field effects on spin-orbit splitting including self-consistent core polarizations

TL;DR

This paper introduces a new method for fitting nuclear energy density functional parameters by focusing on single-particle properties, leading to improved predictions of spin-orbit splittings and magic gaps through adjustments in spin-orbit and tensor couplings.

Contribution

It proposes a novel fitting strategy for nuclear functionals that emphasizes single-particle energies and core polarization effects, resulting in significant improvements over traditional models.

Findings

Adjusted spin-orbit and tensor couplings improve single-particle property predictions

Systematic enhancement of spin-orbit splittings and magic-gap energies

Changes impact nuclear binding energy calculations

Abstract

A new strategy of fitting the coupling constants of the nuclear energy density functional is proposed, which shifts attention from ground-state bulk to single-particle properties. The latter are analyzed in terms of the bare single-particle energies and mass, shape, and spin core-polarization effects. Fit of the isoscalar spin-orbit and both isoscalar and isovector tensor coupling constants directly to the f5/2-f7/2 spin-orbit splittings in 40Ca, 56Ni, and 48Ca is proposed as a practical realization of this new programme. It is shown that this fit requires drastic changes in the isoscalar spin-orbit strength and the tensor coupling constants as compared to the commonly accepted values but it considerably and systematically improves basic single-particle properties including spin-orbit splittings and magic-gap energies. Impact of these changes on nuclear binding energies is also discussed.