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arXiv · 2211.09356

The interplay of single-particle and collective motions in the low-lying states of $^{21}_\Lambda$Ne with quadrupole-octupole correlations

H. J. Xia·X. Y. Wu·H. Mei·J. M. Yao
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Abstract

The beyond mean-field approach for low-lying hypernuclear states is extended by mixing the configurations associated with both single-particle and quadrupole-octupole collective excitations within the generator coordinate method based on a covariant density functional theory. The method is demonstrated in the application to the low-lying states of $^{21}_\Lambda$Ne, where the configurations with the $\Lambda$ hyperon occupying the first ($\Lambda_s$) and second ($\Lambda_p$) lowest-energy states are considered. The results indicate that the positive-parity states are dominated by the $\alpha+^{12}$C+$\alpha+\Lambda_s$ structure. In contrast, the low-lying negative-parity states are dominated by a strong admixture of $\alpha+^{16}$O+$\Lambda_s$ structure and $\alpha+^{12}$C+$\alpha+\Lambda_p$ structure due to the inclusion of octupole correlations. As a result, the low-lying negative-parity states become much lower than what is expected from the previous studies without the mixing, and the electric multipole transition strengths are significantly quenched.

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H. J. Xia, X. Y. Wu, H. Mei, J. M. Yao. 2022-11-17. The interplay of single-particle and collective motions in the low-lying states of $^{21}_\Lambda$Ne with quadrupole-octupole correlations. https://doi.org/10.1007/s11433-022-2045-x

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