Nucleonic Shells and Nuclear Masses

TL;DR

This paper investigates how nuclear masses reveal underlying shell structures and evaluates the predictive power of global models in capturing these shell effects across the nuclear landscape.

Contribution

It introduces a binding-energy indicator to identify shell closures and assesses the accuracy of nuclear mass models in predicting local shell effects.

Findings

Experimental evidence confirms shell closures via nuclear masses.

Global models can predict some shell effects but have limitations.

Shell and subshell closures are systematically cataloged.

Abstract

The binding energy of an isotope is a sensitive indicator of the underlying shell structure as it reflects the net energy content of a nucleus. Since magic nuclei are significantly lighter, or more bound, compared to their neighbors, the presence of nucleonic shell structure makes an imprint on nuclear masses. In this work, using a carefully designed binding-energy indicator, we catalog the appearance of spherical and deformed shell and subshell closures throughout the nuclear landscape. After presenting experimental evidence for shell and subshell closures as seen through the lens of nuclear masses, we study the ability of global nuclear mass models to predict local binding-energy variations related to shell effects.