Initialization effects of nucleon profile on the $\pi$ yields in heavy-ion collisions at medium energies

TL;DR

This study investigates how different nucleon density models affect pion yields in medium-energy heavy-ion collisions, revealing that nucleon correlations influence meson production and yield ratios.

Contribution

It compares the effects of the Skyrme-Hartree-Fock and shell model nucleon density profiles on pion production, highlighting the impact of nucleon correlations.

Findings

Shell model yields produce more pions than SHF.

Double pion ratio varies with impact parameter and model.

Shell model with different basis sizes affects pion yield ratios.

Abstract

We study a problem of $\pi$ production in heavy ion collisions in the context of the Isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) transport model. We generated nucleon densities using two different models, the Skyrme-Hartree-Fock (SHF) model and configuration interaction shell model (SM). Indeed, inter-nucleon correlations are explicitly taken into account in SM, while they are averaged in the SHF model. As an application of our theoretical frameworks, we calculated the $\pi^{-}$ and $\pi^{+}$ yields in collisions of nuclei with $A = 30-40$ nucleons. We used different harmonic oscillator lengths $b_{HO}$ to generate the harmonic oscillator basis for SM in order to study both theoretical and experimental cases. It is found that SM framework with $b_{HO}$ = 2.5 fm and SHF can be distinguished by the yield of $\pi$ mesons, in this case the density distribution calculated by the shell model produces more $\pi$ in the collision. In comparison, SM with $b_{HO}$ = 2.0 fm is characterized from SHF by the double $\pi^{-}/\pi^{+}$ ratios with different large impact parameters, from which one can find the double $\pi^{-}/\pi^{+}$ ratios of SM change smoother and are less than those of SHF.