Relativistic Hartree-Bogoliubov Theory with Finite Range Pairing Forces in Coordinate Space: Neutron Halo in Light Nuclei

The relativistic Hartree Bogoliubov model is applied in the self-consistent mean-field approximation to the description of the neutron halo in the mass region above the $s-d$ shell. Pairing correlations and the coupling to particle continuum states are described by finite range two-body forces. Finite element methods are used in the coordinate space discretization of the coupled system of Dirac-Hartree-Bogoliubov integro-differential eigenvalue equations, and Klein-Gordon equations for the meson fields. Calculations are performed for the isotopic chains of Ne and C nuclei. We find evidence for the occurrence of neutron halo in heavier Ne isotopes. The properties of the $1f-2p$ orbitals near the Fermi level and the neutron pairing interaction play a crucial role in the formation of the halo. Our calculations display no evidence for the neutron halo phenomenon in C isotopes.