Direct mapping of nuclear shell effects in the heaviest elements

TL;DR

This paper reports high-precision mass spectrometry measurements of nobelium and lawrencium isotopes, providing direct evidence of nuclear shell effects and clarifying the location of the island of stability in superheavy elements.

Contribution

It introduces direct mass measurements of superheavy element isotopes, offering new insights into nuclear shell effects and the island of stability.

Findings

Measured binding energies of nobelium and lawrencium isotopes.

Confirmed the deformed shell gap at N=152.

Provided data constraining the island of stability.

Abstract

Quantum-mechanical shell effects are expected to strongly enhance nuclear binding on an "island of stability" of superheavy elements. The predicted center at proton number $Z=114,120$, or $126$ and neutron number $N=184$ has been substantiated by the recent synthesis of new elements up to $Z=118$. However the location of the center and the extension of the island of stability remain vague. High-precision mass spectrometry allows the direct measurement of nuclear binding energies and thus the determination of the strength of shell effects. Here, we present such measurements for nobelium and lawrencium isotopes, which also pin down the deformed shell gap at $N=152$.