Odd nuclei and quasiparticle excitations within the Barcelona Catania Paris Madrid energy density functional

TL;DR

This paper extends the BCPM energy density functional to accurately describe odd-mass nuclei and multiquasiparticle excitations using the equal filling approximation, showing good agreement with experimental data and other models.

Contribution

The paper introduces an extension of the BCPM functional employing the EFA, enabling effective modeling of odd nuclei and quasiparticle excitations, validated against Gogny D1M and experimental results.

Findings

EFA provides results comparable to full blocking in HFB calculations.

BCPM with EFA accurately predicts low-energy spectra.

High-K isomers in $^{178}$Hf are well described.

Abstract

An extension of the Barcelona Catania Paris Madrid (BCPM) energy density functional is proposed to deal with odd-mass systems as well as multiquasiparticle excitations. The extension is based on the assumption that the equal filling approximation (EFA) is a valid alternative to the traditional full blocking procedure of the Hartree-Fock-Bogoliubov method. The assumption is supported by the excellent agreement between full blocking and EFA calculations obtained with different parametrizations of the Gogny interaction. The EFA augmented BCPM functional is used to compute low energy excitation spectra of selected nuclei in different regions of the nuclear chart, and high-$K$ isomers in $^{178}$Hf. We show that BCPM predictions are in good agreement with Gogny D1M results and experimental data.