2alpha+t cluster feature of $3/2^-_3$ state in $^{11}$B

Abstract

We reanalyze $2\alpha+t$ cluster features of $3/2^-$ states in $^{11}$B by investigating the $t$ cluster distribution around a $2\alpha$ core in $^{11}$B, calculated with the method of antisymmetrized molecular dynamics (AMD). In the $3/2^-_3$ state, a $t$ cluster is distributed in a wide region around $2\alpha$, indicating that the $t$ cluster moves rather freely in angular as well as radial motion. From the weak angular correlation and radial extent of the $t$ cluster distribution, we propose an interpretation of a $2\alpha+t$ cluster gas for the $3/2^-_3$ state. In this study, we compare the $2\alpha+t$ cluster feature in $^{11}$B($3/2^-_3$) with the $3\alpha$ cluster feature in $^{12}$C($0^+_2$), and discuss their similarities and differences.