Abstract
A systematic study of the tensor-force impact in neutron-proton drops has been reported using the relativistic Hartree-Fock (RHF) theory with the coupling strength optimized to the relativistic Brueckner-Hartree-Fock (RBHF) results for neutron drops. The evolutions of the neutron spin-orbit splittings as a function of the neutron number for neutron-proton drops with one proton behave similarly to the pure neutron drops, which show the tensor-force effect. By adding one more proton or neutron in the neutron drop with , it is found that the tensor-force effect is more prominent between neutrons and protons than between neutrons. This can be attributed to the isospin factor in the tensor term of the interaction in the RHF density functional theory, which reflects the fact that the neutron-proton tensor force is stronger than the neutron-neutron one. Similar behavior for the spin-orbit splitting evolutions has also been found for the neutron-proton drops with 20 protons, where the tensor-force strength is redetermined according to the RBHF results due to the large central densities of the systems.
- Received 7 May 2020
- Revised 24 July 2020
- Accepted 3 September 2020
DOI:https://doi.org/10.1103/PhysRevC.102.034322
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