Effects of two-particle–two-hole configurations and tensor force on β decay of magic nuclei

Abstract

The $\ensuremath{\beta}$-decay half-lives of four semimagic and magic nuclei, $^{34}\mathrm{Si}, ^{68,78}\mathrm{Ni}$, and $^{132}\mathrm{Sn}$, have been investigated using the self-consistent Hartree-Fock (HF) plus subtracted second random-phase approximation (SSRPA) model with Skyrme energy density functions (EDFs). The inclusion of the two-particle--two-hole (2p-2h) configurations in SSRPA model shifts low-lying Gamow-Teller (GT) states downward. It leads to an increase of the $\ensuremath{\beta}$-decay phase space, which ensures the half-lives of the four nuclei are finite and reduces the $\ensuremath{\beta}$-decay half-lives dramatically. The effect of tensor interaction on the $\ensuremath{\beta}$-decay half-life in the SSRPA model is to change the half-lives greatly by about one to two orders of magnitude with respect to the ones obtained without tensor force.