Nonaxial-octupole effect in superheavy nuclei

TL;DR

This paper predicts the existence of a nonaxial-octupole (Y32) correlation in superheavy nuclei, supported by theoretical calculations, indicating a novel symmetry-breaking effect in the heaviest elements up to atomic number 108.

Contribution

It provides the first concrete theoretical evidence of spontaneous breaking of axial and reflection symmetries due to nonaxial-octupole effects in superheavy nuclei.

Findings

Nonaxial-octupole effects may exist in superheavy elements.

The effect could persist up to element 108.

Theoretical models support the presence of Y32 correlations.

Abstract

The triaxial-octupole Y$_{32}$ correlation in atomic nuclei has long been expected to exist but experimental evidence has not been clear. We find, in order to explain the very low-lying 2$^-$ bands in the transfermium mass region, that this exotic effect may manifest itself in superheavy elements. Favorable conditions for producing triaxial-octupole correlations are shown to be present in the deformed single-particle spectrum, which is further supported by quantitative Reflection Asymmetric Shell Model calculations. It is predicted that the strong nonaxial-octupole effect may persist up to the element 108. Our result thus represents the first concrete example of spontaneous breaking of both axial and reflection symmetries in the heaviest nuclear systems.