A fast-rotating pear-shaped nucleus

TL;DR

This paper reports the discovery of a rapidly rotating pear-shaped nucleus in 100 Ru, revealing new insights into nuclear shape stability, shape evolution, and moments of inertia at high rotational speeds.

Contribution

It presents the first observation of a pear-shaped nucleus in a lighter mass region, rotating nearly three times faster than known cases, and discusses its implications for nuclear shape studies.

Findings

100 Ru exhibits a pear-shaped nucleus at high rotation speeds

The nucleus's moment of inertia remains constant during rotation

Shape evolution occurs with increasing rotational speed

Abstract

The spectroscopic studies have identified few Actinide and Lanthanide nuclei of the periodic table, which can assume the pear shape. The low frequency collective rotation of these nuclei has been established by determining the band structure of the excited levels and their gamma decay rates. In this article, we report the rotation of a pear-shaped nucleus in 100 Ru, which rotates nearly three times faster than the previously known cases. The three novel consequences of this fast rotation are: the realization of a pear-shape in an excited state, its moment of inertia becoming a constant of motion and its shape evolution. These inferences have been arrived at by comparing the characteristics of the rotational band of 100 Ru with three of the best-known examples of a rotating pear-shaped nucleus and through the theoretical interpretation of the data. The observation of a pear-shaped nucleus in the lighter mass region opens up the possibility of a systematic study of the effects of fast rotation on this shape.