Nuclear halo structure and pseudospin symmetry

Nuclear halo structure and conservation of relativistic symmetry are studied within the framework of the relativistic Hartree-Fock-Bogoliubov theory. Giant halos as well as ordinary ones are found in cerium isotopes close to the neutron drip line. Bridged by the T=0 channel, the conservation of pseudospin symmetry (PSS) plays an essential role in stabilizing the neutron halo structures. The Fock terms, especially the ρ-tensor couplings, not only play a significant role in PSS conservation but also present substantial contributions to the T=0 channel, by which the necessity of Fock terms is well demonstrated.