Event-by-Event Jet Quenching and Higher Fourier Moments of Hard Probes

TL;DR

This paper studies how fluctuations in the hot, dense medium created in high-energy nuclear collisions affect measurements of jet quenching and azimuthal asymmetries, highlighting increased uncertainties and potential for new insights.

Contribution

It introduces a model accounting for event-by-event fluctuations in the fireball, revealing their impact on jet quenching observables and proposing methods to estimate spatial inhomogeneities from data.

Findings

Fluctuations can increase the uncertainty in quenching strength q by up to 50%.

Azimuthal asymmetries v2 are affected by spatial inhomogeneities.

Dihadron correlations retain signals of event-by-event quenching, useful for probing fireball inhomogeneity.

Abstract

We investigate the effect of event-by-event fluctuations of the fireball created in high energy nuclear collisions on hard probe observables. We show that spatial inhomogeneities lead to changes in the nuclear suppression factor of high momentum hadrons which can be absorbed in the quenching strength q. This can increase the theoretical uncertainty on extracted values of q by up to 50%. We also investigate effects on azimuthal asymmetries v2 and dihadron correlation functions. The latter show a promising residual signal of event-by-event quenching that might allow us to estimate the size of spatial inhomogeneities in the fireball from experimental data.