Investigating nuclear structure near $N = 32$ and $N = 34$: Precision mass measurements of neutron-rich Ca, Ti and V isotopes

TL;DR

This study provides high-precision mass measurements of neutron-rich calcium, titanium, and vanadium isotopes, refining nuclear shell structure understanding near N=32 and N=34, and challenging previous shell closure assumptions.

Contribution

The paper reports new, more precise mass measurements of specific isotopes, clarifying the existence of shell closures at N=32 and N=34 in neutron-rich nuclei.

Findings

Supports the disappearance of N=32 shell closure with increasing proton number.

Does not support a shell closure at N=34.

Refines the mass surface trends around N=32 and N=34.

Abstract

Nuclear mass measurements of isotopes are key to improving our understanding of nuclear structure across the chart of nuclides, in particular for the determination of the appearance or disappearance of nuclear shell closures. We present high-precision mass measurements of neutron-rich Ca, Ti and V isotopes performed at the TITAN and LEBIT facilities. These measurements were made using the TITAN multiple-reflection time-of-flight mass spectrometer (MR-ToF-MS) and the LEBIT 9.4T Penning trap mass spectrometer. In total, 13 masses were measured, eight of which represent increases in precision over previous measurements. These measurements refine trends in the mass surface around $N = 32$ and $N = 34$, and support the disappearance of the $N = 32$ shell closure with increasing proton number. Additionally, our data does not support the presence of a shell closure at $N = 34$.