Short-range and tensor correlations in $^{4}$He and $^{8}$Be studied with the antisymmetrized quasi-cluster model

Abstract

We apply the tensor version of the antisymmetrized quasi-cluster model (AQCM-T) to $^4\textrm{He}$ and $^8\textrm{Be}$ while focusing on the $NN$ correlations in $\alpha$ clusters. We adopt the $NN$ interactions including realistic ones containing a repulsive core for the central part in addition to the tensor part. In $^4\textrm{He}$, the $pn$ pair in the $^3D$ channel has been known to play a decisive role in the tensor correlation and the framework is capable of treating not only this channel but also the $NN$ correlations in the $^1S$ and $^3S$ channels. In $^8\textrm{Be}$, when two $\alpha$ clusters approach, the $^3D$ pair is suppressed because of the Pauli blocking effect, which also induces a decrease in the $^3S$ component through the $^3S$–$^3D$ coupling. These coherent effects result in the reduction of the attractive effect of the central-even interaction in the middle-range region and keep the distance between two $\alpha$ clusters.