Shell structure of weakly-bound and resonant neutrons

TL;DR

This paper investigates how shell structures of weakly-bound and resonant neutrons evolve near the neutron drip line, explaining observed deformations and predicting possible new ones based on quantum behavior.

Contribution

It provides a systematic analysis of shell structure changes in neutron-rich nuclei using coordinate-space Schrödinger equation solutions with proper asymptotic wave functions.

Findings

Deformation of neutron-rich nuclei with N ≥ 20 explained by shell structure change.

Predicted possible deformation of N ≈ 51 neutron drip-line nuclei.

Demonstrated the importance of low angular momentum states in shell evolution.

Abstract

The systematic change of shell structure in both weakly bound and resonant neutron one-particle levels in nuclei towards the neutron drip line is exhibited, solving the coupled equations derived from the Schr\"{o}dinger equation in coordinate space with the correct asymptotic behaviour of wave functions for $r \rightarrow \infty$. The change comes from the behaviour unique in the one-particle motion with low orbital angular momenta compared with that with high orbital angular momenta. The observed deformation of very neutron-rich nuclei with $N \simgeq 20$ in the island of inversion is a natural result of this changed shell structure, while a possible deformation of neutron-drip-line nuclei with $N \approx 51$, which are not yet observed, is suggested.