Dynamical effects of spin-dependent interactions in low- and intermediate-energy heavy-ion reactions

TL;DR

This paper reviews recent progress in understanding how spin-dependent nuclear interactions influence heavy-ion reactions at intermediate energies, highlighting the potential for new experimental probes of nuclear spin dynamics.

Contribution

It summarizes recent theoretical developments and identifies key spin-sensitive observables in heavy-ion collisions, encouraging further experimental investigation.

Findings

Identification of spin-sensitive observables in models

Potential probes for in-medium non-central nuclear interactions

Emphasis on the need for experimental data

Abstract

It is well known that non-central nuclear forces, such as the spin-orbital coupling and the tensor force, play important roles in understanding many interesting features of nuclear structures. However, their dynamical effects in nuclear reactions are poorly known since only the spin-averaged observables are normally studied both experimentally and theoretically. Realizing that spin-sensitive observables in nuclear reactions may carry useful information about the in-medium properties of non-central nuclear interactions, besides earlier studies using the time-dependent Hartree-Fock approach to understand effects of spin-orbital coupling on the threshold energy and spin polarization in fusion reactions, some efforts have been made recently to explore dynamical effects of non-central nuclear forces in intermediate-energy heavy-ion collisions using transport models. The focuses of these studies have been on investigating signatures of the density and isospin dependence of the form factor in the spin-dependent single-nucleon potential. Interestingly, some useful probes were identified in the model studies while so far there is still no data to compare with. In this brief review, we summarize the main physics motivations as well as the recent progress in understanding the spin dynamics and identifying spin-sensitive observables in heavy-ion reactions at intermediate energies. We hope the interesting, important, and new physics potentials identified in the spin dynamics of heavy-ion collisions will stimulate more experimental work in this direction.