Shape coexistence and $\beta$ decay of ${}^{70}\mathrm{Br}$ within a beyond-mean-field approach

$\beta$-decay properties of the odd-odd $N=Z{}^{70}\mathrm{Br}$ nucleus are self-consistently explored within the beyond-mean-field complex excited vampir variational model using an effective interaction obtained from a nuclear matter $G$-matrix based on the charge-dependent Bonn CD potential and an adequate model space. Results on superallowed Fermi $\beta$ decay of the ground state and Gamow-Teller decay of the $9^{+}$ isomer in ${}^{70}\mathrm{Br}$ correlated with the shape coexistence and mixing effects on the structure and electromagnetic properties of the populated states in the daughter nucleus ${}^{70}\mathrm{Se}$ are presented and compared with available data.

Figure 1

The complex excited vampir spectrum for ${}^{70}\mathrm{Se}$ compared with experimental data [8, 10, 11, 12] (the arrows indicate $E2$ transitions).

Figure 2

The Fermi strength distribution for the decay of the ground state of ${}^{70}\mathrm{Br}$ to ${}^{70}\mathrm{Se}$ obtained within complex excited vampir model.

Figure 3

The Gamow-Teller strength distribution for the decay of the $9^{+}$ isomer in ${}^{70}\mathrm{Br}$ to $8^{+}$ states in ${}^{70}\mathrm{Se}$ obtained within complex excited vampir model.

Figure 4

The same as in Fig. 3, but for ${10}^{+}$ states in ${}^{70}\mathrm{Se}$.

Figure 5

Spectroscopic quadrupole moments of $8^{+}$ Gamow-Teller daughter states in ${}^{70}\mathrm{Se}$.

Figure 6

The same as in Fig. 5, but for ${10}^{+}$ states in ${}^{70}\mathrm{Se}$.

Figure 7

The complex excited vampir Gamow-Teller accumulated strength for the decay of the $9^{+}$ isomer in ${}^{70}\mathrm{Br}$ to $8^{+}$ and ${10}^{+}$ states in ${}^{70}\mathrm{Se}$ compared to the data for $8^{+}$ states [8, 12].