Parity-doublet bands in the odd-\bm{$A$} isotones \element{237}U and \element{239}Pu by a particle-number-conserving method based on the cranked shell model

TL;DR

This study investigates parity-doublet rotational bands in odd-A isotones 237U and 239Pu using a particle-number-conserving cranked shell model, successfully explaining experimental moments of inertia and band splittings through nucleon contributions.

Contribution

The paper introduces a particle-number-conserving method within the cranked shell model to analyze parity-doublet bands, providing detailed explanations of rotational properties and band splittings in actinide isotones.

Findings

Reproduced experimental moments of inertia and angular momentum alignments.

Explained differences in rotational properties between 237U and 239Pu.

Identified nucleon contributions causing band splittings and upbendings.

Abstract

Based on the reflection-asymmetric Nilsson potential, the parity-doublet rotational bands in odd-$A$ isotones \element{237}U and \element{239}Pu have been investigated by using the particle-number-conserving (PNC) method in the framework of the cranked shell model (CSM). The experimental kinematic moments of inertia (MOIs) and angular momentum alignments are reproduced very well by the PNC-CSM calculations. The significant differences of rotational properties between \element{237}U and \element{239}Pu are explained with the contribution of nucleons occupying proton octupole-correlation pairs of $\pi ^{2} i_{13/2}f_{7/2}$. The upbendings of moments of inertia of the parity-doublet bands in \element{237}U are due to the interference terms of alignments of protons occupying $\pi f_{7/2}$ (${1/2}$) and the high-$j$ intruder $\pi i_{13/2}$ $(1/2, 3/2)$ orbitals. The splittings between the simplex partner bands of the parity-doublet bands in both \element{237}U and \element{239}Pu result from the contribution of alignment of neutron occupying the $\nu d_{5/2}$ ($1/2$) orbital.