Impact of temperature dependence of the energy loss on jet quenching observables

TL;DR

This paper investigates how the temperature dependence of parton energy loss influences jet quenching observables in heavy-ion collisions, highlighting the importance of energy loss near the critical temperature for explaining experimental data.

Contribution

It demonstrates that the temperature dependence of energy loss critically affects jet quenching observables, emphasizing the role of energy loss around the critical temperature T_c.

Findings

Large elliptic flow v_2 can be explained by energy loss near T_c.

Quark and gluon R_AA values are nearly equal when energy loss peaks around T_c.

Conversion efficiency of spatial eccentricity into momentum anisotropy is lower than elastic scattering predictions.

Abstract

The quenching of jets (particles with $p_T>>T, \Lambda_{QCD}$) in ultra-relativistic heavy-ion collisions has been one of the main prediction and discovery at RHIC. We have studied, by a simple jet quenching modeling, the correlation between different observables like the nuclear modification factor $\Rapt$, the elliptic flow $v_2$ and the ratio of quark to gluon suppression $R_{AA}(quark)/R_{AA}(gluon)$. We show that the relation among these observables is strongly affected by the temperature dependence of the energy loss. In particular the large $v_2$ and and the nearly equal $\Rapt$ of quarks and gluons can be accounted for only if the energy loss occurs mainly around the temperature $T_c$ and the flavour conversion is significant.Finally we point out that the efficency in the conversion of the space eccentricity into the momentum one ($v_2$) results to be quite smaller respect to the one coming from elastic scatterings in a fluid with a viscosity to entropy density ratio $4\pi\eta/s=1$.