Quantifying a Possibly Reduced Jet-Medium Coupling of the sQGP at the LHC

TL;DR

This paper estimates that the jet-medium coupling in the quark-gluon plasma at LHC energies is about 10% weaker than at RHIC, using a simple energy-loss model and analyzing the nuclear modification factor.

Contribution

It introduces a straightforward method to quantify the reduction in jet-medium coupling at LHC energies compared to RHIC.

Findings

Jet-medium coupling at LHC is approximately 10% smaller than at RHIC.

The measured nuclear modification factor rules out models with energy dependence E^{a>1/3}.

The study constrains jet-energy loss models based on LHC data.

Abstract

The nuclear modification factor R_{AA} measured in Pb+Pb collisions at the Large Hadron Collider (LHC) suggests that the jet-medium coupling in a Quark-Gluon Plasma at LHC energies is reduced as compared to energies reached at the Relativistic Heavy Ion Collider (RHIC). We estimate the reduction factor using a simple generic energy-loss model and find that the jet-medium coupling at the LHC is approximately 10% smaller than at RHIC. Moreover, we examine different jet-energy loss prescriptions with $dE/dx\sim E^a$ and show that the measured momentum dependence of the nuclear modification factor at the LHC rules out any model with $E^{a>1/3}$.