Shell Effects in Nuclei with Vector Self-Coupling of Omega Meson in Relativistic Hartree-Bogoliubov Theory

Abstract

Shell effects in nuclei about the stability line are investigated within the framework of the Relativistic Hartree-Bogoliubov (RHB) theory with self-consistent finite-range pairing. Using 2-neutron separation energies of Ni and Sn isotopes, the role of $σ$- and $ω$-meson couplings on the shell effects in nuclei is examined. It is observed that the existing successful nuclear forces (Lagrangian parameter sets) based upon the nonlinear scalar coupling of $σ$-meson exhibit shell effects which are stronger than suggested by the experimental data. We have introduced nonlinear vector self-coupling of $ω$-meson in the RHB theory. It is shown that the inclusion of the vector self-coupling of $ω$-meson in addition to the nonlinear scalar coupling of $σ$-meson provides a good agreement with the experimental data on shell effects in nuclei about the stability line. A comparison of the shell effects in the RHB theory is made with the Hartree-Fock Bogoliubov approach using the Skyrme force SkP. It is shown that the oft-discussed shell quenching with SkP is not consistent with the available experimental data.