Speaker
Description
Based on the beyond-mean-field Skyrme-Hartree-Fock model, we investigate the shape coexistence in Ne isotopes and the effect of $\Lambda$ hyperon on the energy level structure in the nuclei. The up-to-date Skyrme-type $N\Lambda$ 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 $\beta$ vibrational band are revealed in $^{20,22,24}$Ne. Unlike the previously discovered shrinkage effect of $\Lambda_{s}$ on the ground state nuclei, it is found that the $\Lambda_{s}$ may alter the excitation mode of the second band by affecting the distribution of the collective wave function, thereby causing the $\beta$ vibrational band transitions to a vibrational band with equidistant energy levels.
