# Structure of odd-odd Cs isotopes within the interacting boson-fermion-fermion model based on the Gogny-D1M energy density functional

## TL;DR

This paper models the spectroscopic properties of odd-odd Cs isotopes using an advanced interacting boson-fermion-fermion approach based on microscopic energy density functional calculations, successfully describing their low-energy spectra and band structures.

## Contribution

It introduces a novel microscopic framework combining energy density functional results with the interacting boson-fermion-fermion model to study odd-odd Cs isotopes.

## Key findings

- Accurately reproduces low-lying energy levels of $^{124-132}$Cs.
- Describes band structures based on specific neutron-proton configurations.
- Identifies candidate nuclei for chiral doublet bands.

## Abstract

The spectroscopic properties of the odd-odd isotopes $^{124-132}$Cs have been studied within the interacting boson-fermion-fermion model based on the Gogny-D1M energy density functional framework. Major ingredients to build the interacting boson-fermion-fermion Hamiltonian, such as the ($\beta,\gamma$)-deformation energy surfaces for the even-even core nuclei $^{124-132}$Xe as well as single-particle energies and occupation probabilities of the odd nucleons, have been computed microscopically with the constrained Hartree-Fock-Bogoliubov method. A few coupling constants of the boson-fermion and residual neutron-proton interactions are fitted to reproduce with a reasonable accuracy the experimental excitation energy of the low-lying levels of the odd-mass and odd-odd nuclei. The method is applied to describe the low-energy low-spin spectra of the odd-odd Cs nuclei and the band structures of higher-spin higher-energy states, mainly based on the $(\nu h_{11/2})^{-1}\otimes\pi h_{11/2}$ configuration. Many of those odd-odd Cs nuclei have been identified as candidates for exhibiting chiral doublet bands.