Initialization effect in heavy-ion collisions at intermediate energies

TL;DR

This study investigates how initial conditions influence key observables in heavy-ion collisions at intermediate energies, revealing that initialization effects vary with energy, system size, and observable type, impacting the study of nuclear matter properties.

Contribution

The paper provides a systematic analysis of initialization effects on collision observables using the isospin-dependent BUU model, highlighting their dependence on energy, system size, and observable.

Findings

Initialization effects are moderate for n/p and pion ratios.

Effects are larger for charged pion ratios than n/p ratios.

Lower incident energies and larger impact parameters show more significant initialization effects.

Abstract

Based on the isospin-dependent Boltzmann-Uehling-Uhlenbeck transport model plus the Skyrme force parameters, initialization effect is studied in heavy-ion collision at intermediate energies. We find that there are moderate initialization effects in the observables of free neutron to proton ratio (n/p), pion-/pion + ratio, as well as neutron to proton differential flow (F^x_n-p). Effects of initialization are larger for charged pion-/pion ratios than n/p ratios. And the effects of initialization are more evident in nuclear reactions at lower incident beam energies. We do not see large effects of initialization for light reaction systems or large asymmetric (neutron-richer) reaction systems. We also see relatively large effects of initialization on the neutron to proton differential flow at relatively lower incident beam energies or with large impact parameters. These results may be useful for the delicate studies of Equation of Sate (EoS) of asymmetric nuclear matter.