Beam energy dependence of transverse momentum distribution and elliptic flow in Au-Au collisions using HYDJET++ model

TL;DR

This study uses the HYDJET++ model to analyze how transverse momentum distributions and elliptic flow in Au-Au collisions depend on beam energy, validating the model against experimental data across multiple energies.

Contribution

It demonstrates the effectiveness of HYDJET++ in reproducing particle ratios, spectra, and elliptic flow across a range of collision energies, incorporating freeze-out parameterization and initial-final anisotropy scaling.

Findings

Particle ratios match experimental data, validating the model.

Transverse momentum spectra agree well with experiments.

Elliptic flow $v_2$ scales with initial spatial anisotropy and beam energy.

Abstract

In this work, we present the particle ratios, transverse momentum spectra, and elliptic flow ($v_2$) of $\pi^\pm,k^\pm,$ $p$, and $\bar{p}$ in Au-Au collisions at $\sqrt{s_{NN}}=$ 62.4, 39.0, 27.0, 19.6 and 11.5 GeV using HYDJET++ model. The particle ratios match the experimental data that validates the Cleymans-Reidlich parameterization of freeze-out parameters at lower beam energies under the HYDJET++ framework. The lower collision energies produce a system of high baryon chemical potential ($\mu_B$) and have a lower inelastic cross section. The interplay between these effects affects the overall shape of the $p_T$ spectra. The HYDJET++ model calculations for $p_T$ spectra agree well with the available experimental data. The invariant yield ratio of central and peripheral collisions is independent of beam energy. The elliptic flow is calculated based on the scaling between initial and final azimuthal spatial anisotropy ($k$). This interpretation of $v_2$ successfully describes the experimental data for all the collision energies studied in this work. The positive correlation of $k$ with beam energy leads to a small $v_2$ at lower collision energies. The hadrons containing strange quarks tend to have smaller values of $k$ than the non-strange hadrons.