Tensor Effect on Bubble Nuclei

In the framework of the Hartree–Fock–Bogoliubov (HFB) approach with Skyrme interactions SLy5+T, SLy5+T_w and several sets of TIJ parametrizations, i.e. the Skyrme interaction parametrizations including the tensor terms, the proton density distribution in ³⁴Si and ⁴⁶Ar nuclei is calculated with and without the tensor force. It is shown that the bubble effect in ³⁴Si does not depend a great deal on the Skyrme parametrization and the proton density distribution in ³⁴Si is hardly influenced by the tensor force. As to ⁴⁶Ar, the SLy5+T_w parametrization favors the formation of the bubble structure due to the inversion between the 2s_1/2 and 1d_3/2 orbits (2s_1/2–1d_3/2 inversion). The inversion mechanism induced by the SLy5+T_w interaction is analyzed based on the proton single−particle spectra obtained from the SLy5 and SLy5+T_w interactions as well as the wave functions of the 2s_1/2 and 1d_3/2 states.