Surface-peaked effective mass in the nuclear energy density functional and its influence on single-particle spectra

Abstract

Calculations for infinite nuclear matter with realistic nucleon-nucleon interactions suggest that the isoscalar effective mass of a nucleon at the saturation density, m*/m, equals 0.8 +/- 0.1. This result is at variance with empirical data on the level density in finite nuclei, which are consistent with m*/m ~ 1. Ma and Wambach suggested that these two contradicting results may be reconciled within a single theoretical framework by assuming a radial-dependent effective mass, peaked at the nuclear surface. The aim of this exploratory work is to investigate this idea within the density functional theory by using a Skyrme-type local functional enriched with new terms, $\tau (\nabla \rho {)}^2$ and $\tau \frac{d\rho }{dr}$, where $\tau$ and $\rho$ denote the kinetic and particle densities, respectively. We show that each of these terms can give rise to a surface peak in the effective mass, but of a limited height. We investigate the influence of the radial profile of the effective mass on the spin-orbit splittings and centroids. In particular, we demonstrate that the $\tau \frac{d\rho }{dr}$ term quenches the 1f5/2-1f7/2 splitting in 40Ca, which is strongly overestimated within conventional Skyrme parametrizations.

8 pages, 8 figures, submitted to Phys. Rev. C

References in corpus (7)

• The tensor part of the Skyrme energy density functional. I. Spherical nuclei
• Asymmetric Nuclear Matter from Extended Brueckner-Hartree-Fock Approach
• Covariant theory of particle-vibrational coupling and its effect on the single-particle spectrum
• Spin-orbit and tensor mean-field effects on spin-orbit splitting including self-consistent core polarizations
• Local nuclear energy density functional at next-to-next-to-next-to-leading order
• Global nuclear structure effects of tensor interaction
• Contradicting effective mass scalings within the Skyrme energy density functional method

Cited by in corpus (7)

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• The nuclear energy density functional formalism
• Continuity equation and local gauge invariance for the N3LO nuclear Energy Density Functionals
• Nuclear energy functional with a surface-peaked effective mass: Global properties
• Sensitivity of $\beta$-decay rates to the radial dependence of the nucleon effective mass