Skyrme density functional description of the double magic $^{78}$Ni nucleus

TL;DR

This paper uses Skyrme density functional theory to analyze the nuclear structure of the double magic nucleus $^{78}$Ni, highlighting the importance of tensor interactions in explaining its magicity and level inversion phenomena.

Contribution

It demonstrates the significant role of tensor forces in Skyrme functionals for accurately describing shell structure in exotic nuclei.

Findings

Tensor part affects proton spin-orbit splitting.

Inversion of $1f_{5/2}$ and $2p_{3/2}$ levels confirmed.

Supports previous shell model and experimental results.

Abstract

We calculate the single particle spectrum of the double magic nucleus $^{78}$Ni in a Hartree-Fock approach using the Skyrme density-dependent effective interaction containing central, spin-orbit and tensor parts. We show that the tensor part has an important effect on the spin-orbit splitting of the proton $1f$ orbit which may explain the survival of magicity so far from the stability valley. We confirm the inversion of the $1f5/2$ and $2p3/2$ levels at the neutron number 48 in the Ni isotopic chain expected from previous Monte Carlo shell model calculations and supported by experimental observation.