Revisiting the isospin relaxation time in intermediate-energy heavy-ion collisions

TL;DR

This paper investigates isospin relaxation times in intermediate-energy heavy-ion collisions using a transport model, analyzing the roles of isospin diffusion and drift, and the effects of nuclear symmetry energy and neutron-proton effective mass splitting.

Contribution

It provides a detailed analysis of isospin relaxation mechanisms and the influence of nuclear symmetry energy and effective mass splitting within a lattice Hamiltonian transport model.

Findings

Isospin diffusion and drift are key mechanisms of isospin transport.

Nuclear symmetry energy significantly affects relaxation times.

Neutron-proton effective mass splitting influences isospin dynamics.

Abstract

Isospin relaxation times characterizing isospin transport processes between the projectile and the target with different $N/Z$ ratios and that between the neck and the spectator with different isospin asymmetries and densities in intermediate-energy heavy-ion collisions are studied within an isospin-dependent Boltzmann-Uehling-Uhlenbeck transport model using the lattice Hamiltonian approach. The respective roles and time scales of the isospin diffusion and drift as the major mechanisms of isospin transport in intermediate-energy heavy-ion collisions are discussed. Effects of nuclear symmetry energy and neutron-proton effective mass splitting on the isospin relaxation times are examined.