Effects of Pairing Correlations on Formation of Proton Halo in ⁹C

Properties for the ground state of ⁹C are studied in the relativistic continuum Hartree–Bogoliubov theory with the NLSH, NLLN and TM2 effective interactions. Pairing correlations are taken into account by a density-dependent δ-force with the pairing strength for protons determined by fitting either to the experimental binding energy or to the odd-even mass difference from the five-point formula. The effects of pairing correlations on the formation of proton halo in the ground state of ⁹C are examined. The halo structure is shown to be formed by the partially occupied valence proton levels p_3/2 and p_1/2.