The influence of tensor force on the microscopic heavy-ion interaction potential

TL;DR

This paper investigates how the tensor force influences microscopic heavy-ion interaction potentials, revealing significant effects on fusion barriers especially in medium and heavy spin-unsaturated nuclei, which could impact fusion reaction modeling.

Contribution

The study implements the full Skyrme tensor force into Hartree-Fock and DC-TDHF calculations to quantify its effect on static and dynamic nuclear interaction potentials.

Findings

Tensor force increases static and dynamic fusion barriers in medium/heavy nuclei.

Dynamic effects cause static potentials to be systematically higher.

Tensor force effects are negligible in light systems but significant in heavier nuclei.

Abstract

Background: The tensor interaction is known to play an important role in the nuclear structure studies of exotic nuclei. However, most microscopic studies of low-energy nuclear reactions neglect the tensor force, resulting in a lack of knowledge concerning the effect of the tensor force on HIC...... Purpose: The theoretical study of the influence of the tensor force on heavy-ion interaction potentials is required to further our understanding of the microscopic mechanisms entailed in fusion dynamics. Method: The full Skyrme tensor force is implemented into the static Hartree-Fock and dynamic density-constrained time-dependent Hartree-Fock (DC-TDHF) theory to calculate both static (frozen density) and dynamic microscopic interaction potentials for reactions involving exotic and stable nuclei. Results: The static potentials are found to be systematically higher than the dynamical results, which are attributed to the microscopic dynamical effects included in TDHF. We also show that the dynamical potential barriers vary more significantly by the inclusion of tensor force than the static barriers. The influence of isoscalar and isovector tensor terms is also investigated with the TIJ set of forces. For light systems, the tensor force is found to have an imperceptible effect on the nucleus-nucleus potential. However, for medium and heavy spin-unsaturated reactions, the potentials may change from a fraction of an MeV to almost 2 MeV by the inclusion of tensor force, indicating a strong impact of the tensor force on sub-barrier fusion. Conclusions: The tensor force could indeed play a large role in the fusion of nuclei, with spin-unsaturated systems seeing a systematic increase in ion-ion barrier height and width. This fusion hindrance is partly due to static, ground state effects from the inclusion of the tensor force, though additional hindrance appears when studying nuclear dynamics.