Structure of $^{78}$Ni from first principles computations

TL;DR

This study uses first principles computations to analyze the structure of the doubly magic nucleus $^{78}$Ni, confirming its magic nature and providing insights into its low-lying states for future nuclear shell-model research.

Contribution

It predicts the $J^^+$ state of $^{78}$Ni from correlations with $^{48}$Ca using chiral interactions, advancing understanding of neutron-rich nuclei.

Findings

$^{78}$Ni is confirmed to be doubly magic.

Predicted low-lying states of $^{79,80}$Ni.

Method links states in $^{78}$Ni to those in $^{48}$Ca.

Abstract

Doubly magic nuclei have a simple structure and are the cornerstones for entire regions of the nuclear chart. Theoretical insights into the supposedly doubly magic $^{78}$Ni and its neighbors are challenging because of the extreme neutron-to-proton ratio and the proximity of the continuum. We predict the $J^\pi=2_1^+$ state in $^{78}$Ni from a correlation with the $J^\pi=2_1^+$ state in $^{48}$Ca using chiral nucleon-nucleon and three-nucleon interactions. Our results confirm that $^{78}$Ni is doubly magic, and the predicted low-lying states of $^{79,80}$Ni open the way for shell-model studies of many more rare isotopes.