Structure of Krypton isotopes calculated with symmetry conserving configuration mixing methods

TL;DR

This study uses advanced symmetry-conserving configuration mixing methods to analyze shape transitions and coexistence in krypton isotopes, achieving good agreement with experimental data by including triaxial degrees of freedom.

Contribution

It introduces a comprehensive beyond mean field approach with symmetry restoration and shape mixing to accurately describe krypton isotope structures.

Findings

Shape transitions from oblate to prolate and spherical to oblate are identified.

Low-lying excited states and gamma bands are predicted.

Results align well with experimental observations when triaxiality is included.

Abstract

Shape transitions and shape coexistence in the $^{70-98}$Kr region are studied in a unified view with state-of-the-art beyond self-consistent mean field methods based on the Gogny D1S interaction. Beyond mean field effects are taken into account through the exact angular momentum and particle number restoration and the possibility of axial and non-axial shape mixing. The results of the low-lying properties of these isotopes are in good agreement with the experimental data when the triaxial degree of freedom is included. Shape transitions from axial-oblate ($^{70-72}$Kr) to triaxial-prolate ($^{74-78}$Kr) and from spherical-triaxial ($^{86-92}$Kr) to axial-oblate ($^{94-98}$Kr) ground states are obtained. Additionally, low-lying $0^{+}$ excited states and quasi-gamma bands are found showing the richness of the collective structure in this region.