Shells in a Toroidal Nucleus in the Intermediate Mass Region

TL;DR

This paper investigates the shell structure of toroidal nuclei in the intermediate mass region, revealing stable configurations and proposing methods to produce high-spin and vortex toroidal nuclei with unique properties.

Contribution

It identifies specific toroidal shells with large energy gaps and introduces the concept of vortex nuclei based on nucleon vorticity quantum numbers.

Findings

Existence of toroidal shells with large energy gaps at various nucleon numbers.

Proposal of methods to produce toroidal high-spin isomers.

Introduction of toroidal vortex nuclei based on nucleon vorticity.

Abstract

Attention is fixed on shells in toroidal nuclei in the intermediate mass region using a toroidal single-particle potential. We find that there are toroidal shells in the intermediate mass region with large single-particle energy gaps at various nucleon numbers located at different toroidal deformations characterized by the aspect ratios of toroidal major to minor radius. These toroidal shells provide extra stability at various toroidal deformations. Relative to a toroidal core, Bohr-Mottelson spin-aligning particle-hole excitations may be constructed to occupy the lowest single-particle Routhian energies to lead to toroidal high-spin isomers with different spins. Furthermore, as a nucleon in a toroidal nucleus possesses a vorticity quantum number, toroidal vortex nuclei may be constructed by making particle-hole excitations in which nucleons of one type of vorticity are promoted to populate un-occupied single-particle orbitals of the opposite vorticity. Methods for producing toroidal high-spin isomers and toroidal vortex nuclei are discussed.