Evidence for a change in the nuclear mass surface with the discovery of the most neutron-rich nuclei with 17<Z <25

TL;DR

This study reports the discovery of the most neutron-rich isotopes for elements with atomic numbers 17 to 25, suggesting a possible change in the nuclear mass surface and indicating a new island of inversion.

Contribution

It provides new measurements of neutron-rich nuclei production, including fifteen new isotopes, and suggests potential deviations from existing nuclear mass models.

Findings

Discovery of fifteen new neutron-rich isotopes.

Enhanced production cross sections indicating increased stability.

Possible evidence of a new island of inversion.

Abstract

The results of measurements of the production of neutron-rich nuclei by the fragmentation of a 76-Ge beam are presented. The cross sections were measured for a large range of nuclei including fifteen new isotopes that are the most neutron-rich nuclides of the elements chlorine to manganese (50-Cl, 53-Ar, 55,56-K, 57,58-Ca, 59,60,61-Sc, 62,63-Ti, 65,66-V, 68-Cr, 70-Mn). The enhanced cross sections of several new nuclei relative to a simple thermal evaporation framework, previously shown to describe similar production cross sections, indicates that nuclei in the region around 62-Ti might be more stable than predicted by current mass models and could be an indication of a new island of inversion similar to that centered on 31-Na.