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

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.

Comments: 8 pages, 4 figures