# Nucleon spin polarization in intermediate-energy heavy-ion collisions

## TL;DR

This study investigates nucleon spin polarization in intermediate-energy heavy-ion collisions using a spin-dependent transport model, highlighting the dominant role of the spin-orbit potential and exploring effects of energy, impact parameter, and theoretical uncertainties.

## Contribution

It extends previous relativistic studies to intermediate energies, incorporating spin-dependent potentials via the lattice Hamiltonian method to analyze spin polarization mechanisms.

## Key findings

- Global and local spin polarizations are mainly influenced by the time-odd component of the nuclear spin-orbit potential.
- The study discusses how beam energy and impact parameter affect nucleon spin polarization.
- The results provide a baseline for understanding spin polarization in strongly interacting matter in heavy-ion collisions.

## Abstract

Based on a spin-dependent Boltzmann-Uehling-Uhlenbeck transport model with spin-dependent potentials incorporated using the lattice Hamiltonian method, we have studied the global spin polarization perpendicular to the reaction plane as well as the local spin polarization in the longitudinal direction in non-central intermediate-energy heavy-ion collisions, as an extension of similar studies in relativistic heavy-ion collisions. Both the global and the local spin polarizations are found to be mostly dominated by the time-odd component of the nuclear spin-orbit potential. Impacts of various theoretical uncertainties on the nucleon spin polarization as well as its dependence on the beam energy and impact parameter are discussed. Our study serves as a baseline for understanding the spin polarization mechanism of strongly interacting matter produced in heavy-ion collisions dominated by nucleon degree of freedom.