Structural evolution in $A\approx 100$ nuclei within the mapped interacting boson model based on the Gogny energy density functional

TL;DR

This study models the structural evolution of neutron-rich nuclei around mass 100 using a mapped interacting boson model informed by Gogny energy density functional calculations, revealing shape coexistence and gamma-soft behavior.

Contribution

It introduces a microscopic-mapped IBM approach based on Gogny EDF to predict nuclear shapes and spectra in the $A oughly 100$ region, integrating mean-field and boson models.

Findings

Predicted gamma-soft behavior in Ru and Mo nuclei.

Identified shape coexistence in Zr and Sr nuclei.

Accurately described experimental energy levels and transition probabilities.

Abstract

The structure of even-even neutron-rich Ru, Mo, Zr and Sr nuclei in the $A\approx 100$ mass region is studied within the interacting boson model (IBM) with microscopic input from the self-consistent mean-field approximation based on the Gogny-D1M energy density functional. The deformation energy surface in the quadrupole deformation space $(\beta,\gamma)$, computed within the constrained Hartree-Fock-Bogoliubov framework, is mapped onto the expectation value of the appropriately chosen IBM Hamiltonian with configuration mixing in the boson condensate state. The mapped IBM Hamiltonian is used to study the spectroscopic properties of $^{98-114}$Ru, $^{96-112}$Mo, $^{94-110}$Zr and $^{92-108}$Sr. Several cases of $\gamma$-soft behavior are predicted in Ru and Mo nuclei while a pronounced coexistence between strongly-prolate and weakly-oblate deformed shapes is found for Zr and Sr nuclei. The method describes well the evolution of experimental yrast and non-yrast states as well as selected $B$(E2) transition probabilities.