Shape coexistence in Ne isotopes and hyperon impurity effect on low-lying states

TL;DR

This study uses a beyond-mean-field Skyrme-Hartree-Fock model to analyze shape coexistence in Ne isotopes and the impact of hyperons on their low-lying energy states, aligning well with experimental data.

Contribution

It introduces a detailed investigation of hyperon effects on nuclear shape coexistence and excitation modes in Ne isotopes using advanced Skyrme interactions.

Findings

Identification of shape coexistence in Ne isotopes.

Hyperon impurity can alter excitation modes.

Good agreement with experimental energy spectra.

Abstract

Based on the beyond-mean-field Skyrme-Hartree-Fock model, we investigate the shape coexistence in Ne isotopes and the effect of $\la$ hyperon on the energy level structure in the nuclei. The up-to-date Skyrme-type $N\la$ interaction SLL4 and the $NN$ interaction SGII are employed. Low-lying energy spectra of $^{20,22,24,26,28,30,32,34}$Ne, including the low-lying states with $J\leq 6$, are predicted, discussed in detail, and found in good agreement with experimental results. The electric quadrupole transition rate is also examined. The coexistences of a ground state rotational band and a $\be$ vibrational band are revealed in $^{20,22,24}$Ne. Unlike the previously discovered shrinkage effect of $\la_{s}$ on the ground state nuclei, it is found that the $\la_{s}$ may alter the excitation mode of the second band by affecting the distribution of the collective wave function, thereby causing the $\be$ vibrational band transitions to a vibrational band with equidistant energy levels.