Studies of Deformed Halo Structures of 39Na and 42Mg

Background: The recent experimental discovery of drip-line nucleus Na-39 has attracted great interest in theoretical studies of exotic nuclear structures in this mass region. Methods: We solve the Skyrme-Hartree-Fock-Bogoliubov (Skyrme-HFB) equation within deformed coordinate-spaces. The present approach is suitable for descriptions of weakly bound deformed nuclei with continuum effects and deformed halo structures. Results: The systematical two-neutron separation energies are obtained with the SkM(ext1)* and UNEDF0(ext1) forces for Na and Mg isotopes close to the neutron drip line. The density distributions show that Na-39 and Mg-42 have deformed halo structures. Furthermore, there are significant influences of various pairing interactions on halo shapes at large distances. Conclusions: Both Na-39 and Mg-42 are very weakly bound with well prolate deformed cores. However, their surface halo structures are dependent on the choices of pairing interactions. The volume-type pairing interaction tends to predict a prolate deformed halo, while the halo deformations at large distances are reduced by adopting the surface pairing. We demonstrate that 39Na and 42Mg are promising candidates for two-neutron deformed halo nuclei.

Automated summary

This study investigates the exotic nuclear structures of Na-39 and Mg-42, which are weakly bound but have deformed halo structures. The results also demonstrate the significant influences of various pairing interactions on halo shapes.