Impurity effect of Lambda hyperon on collective excitations of atomic nuclei

Abstract

Taking the ground state rotational band in ${}^{24}$Mg as an example, we investigate the impurity effect of $\Lambda$ hyperon on collective excitations of atomic nuclei in the framework of non-relativistic energy density functional theory. To this end, we take into account correlations related to the restoration of broken symmetries and fluctuations of collective variables by solving the eigenvalue problem of a five-dimensional collective Hamiltonian for quadrupole vibrational and rotational degrees of freedom. The parameters of the collective Hamiltonian are determined with constrained mean-field calculations for triaxial shapes using the SGII Skyrme force. We compare the low-spin spectrum for ${}^{24}$Mg with the spectrum for the same nucleus inside ${}_{\Lambda }^{25}$Mg. It is found that the $\Lambda$ hyperon stretches the ground state band and reduces the $B(E2:2_1^{+}\to 0_1^{+})$ value by $\sim 9$, mainly by softening the potential energy surface towards the spherical shape, even though the shrinkage effect on the average proton radius is only $\sim 0.5$.

16 pages, 5 figures, and 1 table

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Cited by in corpus (19)

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• Description of single-Lambda hypernuclei with relativistic point coupling model
• Enhanced collectivity in neutron-deficient Sn isotopes in energy functional based collective Hamiltonian
• Microscopic particle-rotor model for low-lying spectrum of Lambda hypernuclei
• Triaxially deformed relativistic point-coupling model for $\Lambda$ hypernuclei: a quantitative analysis of hyperon impurity effect on nuclear collective properties
• Generator coordinate method for hypernuclear spectroscopy with a covariant density functional
• Beyond-mean-field study of the hyperon impurity effect in hypernuclei with shape coexistence
• Effect of pairing correlations on nuclear low-energy structure: BCS and general Bogoliubov transformation
• Relation between shrinkage effect and compression of rotational spectrum in ${}_{\Lambda }^7$Li hypernucleus
• Application of random phase approximation to vibrational excitations of double-$\Lambda$ hypernuclei
• Collective excitations of $\Lambda$ hypernuclei
• A relativistic mean field study of multi-strange system
• Impurity effect of Lambda particle on the structure of 18F and 19F_Lambda
• Sum rule approach to a soft dipole mode in $\Lambda$ hypernuclei
• Probable alpha and $14$^C cluster emission from hyper Ac nuclei
• Tetrahedral shape and Lambda impurity effect in ${}^{80}$Zr with a multidimensionally constrained relativistic Hartree-Bogoliubov model
• Impurity effect of $\Lambda$ hyperon on shape-coexistence nucleus ${}^{44}$S in the energy functional based collective Hamiltonian
• Reaction cross sections of hypernuclei and the shrinkage effect