Relativistic mean-field description of light $\Lambda$ hypernuclei with large neutron excess

The Relativistic Hartree Bogoliubov model in coordinate space, with finite range pairing interaction, is applied to the description of by stabilizing an otherwise unbound core nucleus. The additional binding of the halo neutrons to the core originates from the increase in magnitude of the spin-orbit term. Although the $\Lambda$ produces only a fractional change in the central mean-field potential, through a purely relativistic effect it increases the spin-orbit term which binds the outermost neutrons