The energy staggering of the alternating parity band in pear-shaped nuclei

“Horia Hulubei” National Institute for R&D in Physics and Nuclear Engineering - Str. Reactorului 30, RO-077125, POB-MG6 Bucharest-Maˇgurele, Romania and Academy of Romanian Scientists - Splaiul Independenţei 54, RO-050044, Bucharest, Romania

Received: 14 April 2025
Accepted: 23 July 2025

Abstract

The dynamical evolution of the parity splitting energy shift observed in the spectra of even-even nuclei with strong octupole correlations is described in a collective model. The theoretical formalism reproduces the low spin pattern of the odd-even staggering in the alternate parity bands of the considered nuclei, by assuming a parity-specific evolution of the intrinsic potential associated with the quadrupole-octupole interaction. It is found that the positive parity bands have a more stabilized octupole deformation. The reduced number of the model parameters and their established phenomenological roles, allow to systemize the variation of the abnormal staggering effects as a function of nucleon numbers. The consequences of the distinct structure for the opposite parity states are explored within their corresponding electromagnetic properties.