Microscopic description of structural evolution in Pd, Xe, Ba, Nd, Sm, Gd and Dy isotopes

TL;DR

This study uses microscopic models to analyze shape evolution and triaxiality in various isotopes, identifying candidates for E(5) and X(5) symmetries and comparing results with experimental data.

Contribution

It provides a detailed microscopic analysis of nuclear shape evolution in multiple isotopic chains using RHB and TPSM, highlighting candidates for critical-point symmetries.

Findings

Identification of isotopes with flat PESs as E(5) candidates

Recognition of nuclei with bump-shaped PESs as X(5) candidates

Good agreement with experimental data and other models

Abstract

Aiming to understand the role of triaxiality and the evolution of the ground state nuclear shapes, we have carried out a microscopic study for a series of chains of Pd, Xe, Ba, Nd, Sm, Gd, and Dy isotopes. This is done within the self-consistent Relativistic-Hartree-Bogoliubov (RHB) formalism, and supported by the Triaxial Projected Shell Model (TPSM) approach. Pairing interaction separable in the momentum space with DD-ME2 force parameter is used to generate the potential energy surfaces(PESs) under the axial and triaxial symmetry. Shape evolution manifest themself in very clear manner in almost all the isotopic chains. Properties of the global mimima have been found to be in good agreement with the available experimental data. Relatively flat PESs, and $\gamma$-soft nature, have been suggested $^{108,110}$Pd, $^{132,134}$Xe and $^{134}$Ba as good candidates for E(5) symmetry, while $^{102}$Pd is not found suitable for E(5) symmetry. The PESs with a bump, and rigidity against triaxial variable($\gamma$) suggested $^{150}$Nd, $^{152}$Sm and $^{154}$Gd to be good candidates while $^{150}$Sm and $^{156}$Dy are poor candidates of X(5) critical-point symmetry. The findings of the present RHB calculations supported by TPSM are qualitatively in good agreement with the experimental and other theoretical calculations.