Magicity of neutron-rich isotopes within relativistic self-consistent approaches

Abstract

The formation of new shell gaps in intermediate mass neutron-rich nuclei is investigated within the relativistic Hartree-Fock-Bogoliubov theory, and the role of the Lorentz pseudo-vector and tensor interactions is analyzed. Based on the Foldy-Wouthuysen transformation, we discuss in detail the role played by the different terms of the Lorentz pseudo-vector and tensor interactions in the appearing of the $N=16$, 32 and 34 shell gaps. The nuclei ${}^{24}$O, ${}^{48}$Si and ${}^{52,54}$Ca are predicted with a large shell gap and zero (${}^{24}$O, ${}^{52}$Ca) or almost zero (${}^{48}$Si, ${}^{54}$Ca) pairing gap, making them candidates for new magic numbers in exotic nuclei. We find from our analysis that the Lorentz pseudo-vector and tensor interactions induce very specific evolutions of single-particle energies, which could clearly sign their presence and reveal the need for relativistic approaches with exchange interactions.

Comments: 7 pages, 5 figures, 1 table