Fourier Harmonics of High-pT Particles Probing the Fluctuating Intitial Condition Geometries in Heavy-Ion Collisions

TL;DR

This paper investigates how high-pT particle azimuthal harmonics in heavy-ion collisions are influenced by initial geometry models and early-time evolution, revealing certain harmonics' insensitivity to initial conditions and their potential to distinguish initial state models.

Contribution

It introduces a generalized energy-loss model for high-pT particles and analyzes the sensitivity of higher azimuthal harmonics to initial condition models and early-time dynamics.

Findings

Higher jet harmonics are insensitive to initial condition models.

The correlation between nuclear modification factors effectively differentiates initial geometries.

High-pT second harmonic is most affected by early-time evolution.

Abstract

Second Fourier harmonics of jet quenching have been thoroughly explored in the literature and shown to be sensitive to the underlying jet path-length dependence of energy loss and the differences between the mean eccentricity predicted by Glauber and CGC/KLN models of initial conditions. We compute the jet path-length dependence of energy-loss for higher azimuthal harmonics of jet-fragments in a generalized model of energy-loss for RHIC energies and find, however, that even the high-$p_T$ second moment is most sensitive to the poorly known early-time evolution during the first fm/c. Moreover, we demonstrate that higher-jet harmonics are remarkably insensitive to the initial conditions, while the different $v_n(N_{part})$ vs. $v_n^{I_{AA}}(N_{part})$ correlations between the moments of monojet and dijet nuclear modifications factors remain a most sensitive probe to differentiate between Glauber and CGC/KLN initial state sQGP geometries.