Experimental balance energies and isospin-dependent nucleon-nucleon cross-sections

TL;DR

This study investigates how isospin-dependent nucleon-nucleon cross-sections influence the balance energies in nuclear collisions, revealing sensitivity in light systems and providing a model that aligns with experimental data.

Contribution

It demonstrates the impact of isospin-dependent cross-sections on balance energies and introduces a power law relation with mass and N/Z dependence.

Findings

Balance energies are sensitive to isospin effects in light systems.

A reduced cross-section with a stiff EoS explains most experimental balance energies.

Balance energy follows a power law with mass and N/Z ratio.

Abstract

The effect of different isospin-dependent cross-section on directed flow is studied for variety of systems(for which experimental balance energies are available) using an isospin-dependent Quantum Molecular Dynamic (IQMD) model. We show that balance energies are sensitive towards isospin-dependent cross-sections for light systems, while nearly no effect exist for heavier nuclei. A reduced cross-section $\sigma = 0.9\sigma_{NN}$ with stiff equation of state is able to explain experimental balance energies in most of systems. A power law behaviour is also given for the mass dependence of balance energy, which also follow N/Z dependence.