Structures in 9Be, 10Be and 10B studied with tensor-optimized shell model

Abstract

We investigate the structures of $^{9,10}$Be and $^{10}$B with the tensor-optimized shell model (TOSM) using the effective interaction based on the bare nucleon-nucleon interaction AV8$^\prime$. The tensor correlation is treated in TOSM with the full optimization of 2p2h configurations including high-momentum components. The short-range correlation is described in the unitary correlation operator method (UCOM). It is found that the level orders of the low-lying states of $^{9,10}$Be and $^{10}$B are entirely reproduced. For $^9$Be, ground band states are located relatively in higher energy than the experiments, which indicates the missing $\alpha$ clustering correlation in these states as seen in the case of $^8$Be with TOSM. In addition, the tensor force gives the larger attraction for $T$=1/2 states than for $T$=3/2 ones for $^9$Be. For $^{10}$Be, the tensor contribution of $0^+_2$ shows the largest value among the $0^+$ states. This can be related to the $\alpha$ clustering correlation in this state. It is also found that the level order of three nuclei depends on the tensor force in comparison with the results obtained with the Minnesota interaction without the tensor force.