Continuum Skyrme Hartree-Fock-Bogoliubov theory with Green's function method for neutron-rich Ca, Ni, Zr, and Sn isotopes

The possible exotic nuclear properties in the neutron-rich Ca, Ni, Zr, and Sn isotopes are examined with the continuum Skyrme Hartree-Fock-Bogoliubov theory in the framework of the Green's function method. The pairing correlation, the couplings with the continuum, and the blocking effects for the unpaired nucleon in odd-A nuclei are properly treated. The Skyrme interaction SLy4 is adopted for the ph channel and the density-dependent d interaction is adopted for the pp channel, which well reproduce the experimental two-neutron separation energies Sen and one-neutron separation energies S-n . It is found that the criterion S-n > 0 predicts a neutron drip line with neutron numbers much smaller than those for S-2n > 0. Owing to the unpaired odd neutron, the neutron pairing energies -E-pair in odd-A nuclei are much lower than those in the neighbor-ing even-even nuclei. By investigating the single-par ticle structures, the possible halo structures in the neutron-rich Ca, Ni, and Sn isotopes are predicted, where sharp increases in the root-mean-square (rms) radii with significant deviations from the traditional r ? A(1/3) rule and diffuse spatial density distributions are observed. Analyzing the contributions of various partial waves to the total neutron density p(lj)(r)/p(r) reveals that the orbitals located around the Fermi surface-particularly those with small angular momenta-significantly affect the extended nuclear density and large rms radii. The number of neutrons N-? (N-0 ) occupying above the Fermi surface ?(n) (continuum threshold) is discussed, whose evolution as a function of the mass number A in each isotope is consistent with that of the pairing energy, supporting the key role of the pairing correlation in halo phenomena.

Automated summary

The possible exotic nuclear properties in neutron-rich Ca, Ni, Zr, and Sn isotopes were studied using the continuum Skyrme Hartree-Fock-Bogoliubov theory and the Green's function method. The effects of pairing correlation, couplings with continuum, and blocking effects were properly considered. The study found that the neutron-rich isotopes show different properties depending on the criteria used for neutron drip line prediction, and the presence of unpaired odd neutron leads to lower neutron pairing energies in odd-A nuclei compared to neighbor-ing even-even nuclei. Possible halo structures were predicted in neutron-rich Ca, Ni, and Sn isotopes, characterized by significant deviations from the traditional r ? A(1/3) rule and diffuse spatial density distributions. The contributions of various partial waves to the neutron density were analyzed, and it was found that orbitals near the Fermi surface, particularly those with small angular momenta, significantly affect the extended nuclear density and large rms radii. The evolution of the number of neutrons above the Fermi surface as a function of mass number A is consistent with the pairing energy, supporting the important role of pairing correlation in halo phenomena.