Shape coexistence in lead isotopes in the interacting boson model with a Gogny energy density functional

Abstract

We investigate the emergence and evolution of shape coexistence in the neutron-deficient lead isotopes within the interacting boson model (IBM) plus configuration mixing with microscopic input based on the Gogny energy density functional (EDF). The microscopic potential-energy surface obtained from the constrained self-consistent Hartree-Fock-Bogoliubov method employing the Gogny-D1M EDF is mapped onto the coherent-state expectation value of the configuration mixing IBM Hamiltonian. In this way, the parameters of the IBM Hamiltonian are fixed for each of the three relevant configurations (spherical, prolate, and oblate) associated to the mean-field minima. Subsequent diagonalization of the Hamiltonian provides the excitation energy of the low-lying states and transition strengths among them. The model predictions for the ${0}^{+}$ level energies and evolving shape coexistence in the considered lead chain are consistent both with experiment and with the indications of the Gogny-EDF energy surfaces.