A proton-neutron QRPA Calculation of the β- Decay of Nd152 using the Fayans Energy Density Functional

Abstract

This paper presents a calculation of the β– decay of the neutron-rich nucleus Nd152 using the proton-neutron Quasi-particle Random Phase Approximation (pnQRPA) model. The single-particle ground states are calculated self-consistently using the Fayans energy density functional in a Hartree-Fock-Bogoliubov (HFB) scheme for deformed nuclei. The quasi-particle states which are needed for the pnQRPA calculation are calculated from the HFB single-particle ground states using the Bardeen-Cooper-Schriefer (BCS) approximation. Only Gamow-Teller β– excitations are considered, and two kinds of excitation force are used to excite the daughter nucleus to produce the β– decay: (a) a pure Migdal force, and (b) a Migdal force plus a correction term obtained self-consistently from the BCS quasi-particle basis. The calculations with the pure Migdal force and the corrected Migdal force give half-lives of 5.92 min and 6.91 min, respectively, which are about one half of the experimental value of 11.6(7) min, and decay energies of 1.38 MeV and 1.33 MeV, respectively, both close to the experimental decay energy of 1.12 MeV. The correction to the Migdal excitation force turns out to improve the accuracy of the calculations.