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arXiv · 1811.01486

Beyond mean-field approach for pear-shaped hypernuclei

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

We develop both relativistic mean field and beyond approaches for hypernuclei with possible quadrupole-octupole deformation or pear-like shapes based on relativistic point-coupling energy density functionals. The symmetries broken in the mean-field states are recovered with parity, particle-number, and angular momentum projections. We take $^{21}_Λ$Ne as an example to illustrate the method, where the $Λ$ hyperon is put on one of the two lowest-energy orbits (labeled as $Λ_s, Λ_p$), respectively. We find that the $Λ$ hyperon in both cases disfavors the formation of a reflection-asymmetric molecular-like $^{16}$O$+α$ structure in $^{20}$Ne, which is consistent with the Nilsson diagram for the hyperon in $(β_2, β_3)$ deformation plane. In particular, we show that the negative-parity states with the configuration $^{20}$Ne($K^π=0^-)\otimes Λ_s$ are close in energy to those with the configuration $^{20}$Ne($K^π=0^+)\otimes Λ_p$, even though they have very different structures. The $Λ_s$ ($Λ_p$) becomes more and more concentrated around the bottom (top) of the "pear" with the increase of octupole deformation.

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H. J. Xia, X. Y. Wu, H. Mei, J. M. Yao. 2018-11-05. Beyond mean-field approach for pear-shaped hypernuclei. https://doi.org/10.1007/s11433-018-9308-0

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