Gamow-Teller transitions and proton-neutron pair correlation in $N=Z=$ odd $p$-shell nuclei

Abstract

We have studied the Gamow-Teller (GT) transitions from $N=Z+2$ neighbors to $N=Z=$ odd nuclei in $p$-shell region by using isospin-projected and $\beta \gamma$-constraint antisymmetrized molecular dynamics combined with generator coordinate method. The calculated GT transition strengths from $0^{+}1$ states to $1^{+}0$ states such as ${}^6\text{He}(0_1^{+}1)\to {}^6\text{Li}(1_1^{+}0)$, ${}^{10}\text{Be}(0_1^{+}1)\to {}^{10}\text{B}(1_1^{+}0)$, and ${}^{14}\text{C}(0_1^{+}1)\to {}^{14}\text{N}(1_2^{+}0)$ exhaust more than 50\% of the sum rule. These $N=Z+2$ initial states and $N=Z=$ odd final states are found to dominantly have $S=0,T=1$ $nn$ pairs and $S=1,T=0$ $pn$ pairs, respectively. Based on two-nucleon ($NN$) pair picture, we can understand the concentration of the GT strengths as the spin-isospin-flip transition $nn(S=0,T=1)\to pn(S=1,T=0)$ in $LS$-coupling scheme. The GT transition can be a good probe to identify the spin-isospin partner states with $nn$ pairs and $pn$ pairs of $N=Z+2$ and $N=Z=$ odd nuclei, respectively.

Comments: 21 pages, 3 figures