Narrow Results

In a shell-model calculation with traditional effective charges, theoretical B(E2) values are larger than experimental values for neutron-rich carbon isotopes ¹⁶C and ¹⁸C. Using the shell-model with 2ħw excitations in the first order perturbation theory, we investigate the B(E2) values and the effective charges for stable and neutron-rich carbon isotopes.

The γ-unstable limit of the interacting boson model for identical nucleon systems (IBM-I) was studied within the framework of the SD-pair shell model. The results show that the properties of this limit as realized within the boson picture can be reproduced well within a fermion framework.

The nonrelativistic Skyrme energy density functional (EDF) based collective Hamiltonian, that takes into account dynamical correlations related to the restoration of broken symmetries and fluctuations of quadrupole collective variables, is applied to quantitatively study the impurity effect of Λ hyperon on the collectivity of ⁴⁴S. Several Skyrme forces for both the nucleon–nucleon (NN) and Λ-nucleon (ΛN) interactions are used. The influence of pairing strengths on the polarization effect of Λ hyperon is also examined. It is found that although these Skyrme forces with different pairing strengths give somewhat different low-lying spectra for ⁴⁴S, all of them give similar and generally small size of Λ reduction effect (within 5%) on the collective properties.