The southern shore of the island of inversion studied via quasi-free scattering

TL;DR

This paper investigates the structure of neutron-rich O and F isotopes near the Island of Inversion using quasi-free scattering, revealing the breakdown of N=20 magicity and signs of superfluidity.

Contribution

It presents new experimental data on neutron-rich isotopes and combines them with advanced shell-model and ab-initio calculations to deepen understanding of nuclear structure in this region.

Findings

Breakdown of N=20 magicity in O and F isotopes

Evidence of superfluid regime in 28O and 29F

Insights into deformation and halo formation

Abstract

Neutron-rich nuclei exhibit a variety of intriguing features associated with nuclear structure evolution, deformation, and other phenomena. Particularly interesting is the region in the chart of nuclides around Z = 12 and N = 20, commonly referred to as "Island of Inversion", which is profoundly influenced by these features. Recent cutting-edge experiments performed at SAMURAI/RIBF have investigated the structure of the most neutron-rich O and F isotopes, including 27,28O and 28-30F, utilizing quasi-free scattering and invariant-mass spectroscopy techniques. This experimental campaign manifests the breakdown of the N = 20 magicity for O and F isotopes, placing them within the "Island of Inversion", as is discussed in this review article. The results are further supported by theoretical analyses employing state-of-the-art shell-model and ab-initio calculations. These nuclei serve as corner stones for the study of weak binding and continuum coupling, deformation, and halo formation. Signatures for the establishment of a superfluid regime in 28O and 29F are found. Future experimental and theoretical studies are needed to examine details.