A mean field study of single-particle spectra evolution in Z=14 and N=28 chains

We study the mechanisms which reduce the proton 1d(3/2)-1d(5/2) spin-orbit splitting and the neutron 1f(7/2) subshell closure in 42Si. We use various self-consistent mean field models: non-relativistic Skyrme-Hartree-Fock and relativistic density-dependent Hartree-Fock. Special attention is devoted to the influence of a tensor component in the effective interaction. It is found that the tensor force indeed governs the reduction of the 1d proton spin-orbit splitting. On the other hand, the reduction of the neutron 1f(7/2) subshell closure is not clearly related to the tensor force.