Differential elliptic flow of identified hadrons and constituent quark number scaling at FAIR

TL;DR

This study investigates elliptic flow of identified hadrons at FAIR energies using UrQMD and AMPT models, revealing mass ordering, baryon-meson crossing, and constituent quark number scaling behaviors with model-dependent differences.

Contribution

It compares hadronic and partonic transport models in predicting elliptic flow and constituent quark scaling at FAIR energies, highlighting differences in scaling behavior.

Findings

Both models show mass ordering of $v_2$ at low $p_T$

AMPT produces higher $v_2$ than UrQMD

UrQMD exhibits better $KE_T$ scaling than AMPT

Abstract

Differential elliptic flow $v_2(p_{T})$ for identified hadrons has been investigated in the FAIR energy regime, employing a hadronic-string transport model (UrQMD) as well as a partonic transport model (AMPT). It has been observed that both the models show a mass ordering of $v_2$ at low $p_{T}$ and a switch over resulting a baryon-meson crossing at intermediate $p_{T}$. AMPT generates higher $v_2$ values compared to UrQMD. In addition, constituent quark number scaling behavior of elliptic flow has also been addressed. Scaling behavior in terms of the transverse momentum $p_T$ is found to absent for both the partonic as well as the hadronic model. However UrQMD and AMPT with string melting scenario do exhibit a NCQ scaling of $v_2$ at varying degree, with respect to transverse kinetic energy $KE_T$. But default AMPT, where partonic scatterings are not included, does not show any considerable scaling behavior. A variable $\alpha$ is defined to quantify the degree of $KE_T$ scaling. We found that UrQMD gives better scaling than AMPT at FAIR.