Probing high-density behavior of symmetry energy from pion emission in heavy-ion collisions

TL;DR

This study uses the ImIQMD model to analyze pion emission in heavy-ion collisions at 1 A GeV, providing insights into the high-density behavior of nuclear symmetry energy by comparing simulations with experimental data.

Contribution

It systematically investigates pion production as a probe of symmetry energy at supra-saturation densities using various Skyrme parameters and symmetry energy stiffness models.

Findings

Preliminary results favor a hard symmetry energy with γ_s=2.

Pion multiplicities and π−/π+ ratios are sensitive to symmetry energy stiffness.

Model comparisons align with FOPI experimental data.

Abstract

Within the framework of the improved isospin dependent quantum molecular dynamics (ImIQMD) model, the emission of pion in heavy-ion collisions in the region 1 A GeV as a probe of nuclear symmetry energy at supra-saturation densities is investigated systematically, in which the pion is considered to be mainly produced by the decay of resonances $\triangle$(1232) and N*(1440). The total pion multiplicities and the $\pi^{-}/\pi^{+}$ yields are calculated for selected Skyrme parameters SkP, SLy6, Ska and SIII, and also for the cases of different stiffness of symmetry energy with the parameter SLy6. Preliminary results compared with the measured data by the FOPI collaboration favor a hard symmetry energy of the potential term proportional to $(\rho/\rho_{0})^{\gamma_{s}}$ with $\gamma_{s}=2$.