Charged-particle jet spectra in event-shape engineered Pb--Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV with ALICE

TL;DR

This paper presents new measurements of charged-particle jet spectra in Pb--Pb collisions at 5.02 TeV, using event-shape engineering to better understand jet quenching and path-length dependence in heavy-ion collisions.

Contribution

It introduces the application of event-shape engineering to measure jet spectra, providing improved constraints on jet-medium interactions compared to traditional methods.

Findings

Jet spectra vary with event shape, indicating path-length dependence.

Event-shape engineering reduces initial-state fluctuations.

Results improve understanding of jet quenching mechanisms.

Abstract

The path-length dependence of jet quenching can help to constrain different jet quenching mechanisms in heavy-ion collisions. However, measuring an explicit value for this dependence has proven challenging. Traditional approaches, which consider anisotropic jet suppression arising from geometric asymmetries, have successfully measured a non-zero azimuthal dependence of jet modification with respect to the event-plane angle of the collision. While such signals improve our qualitative understanding of this topic, extraction of an explicit dependence from these results is limited by fluctuations in the initial state and jet--medium interactions. A new approach to characterize the geometry of the collision is to use event-shape engineering, a technique that classifies events within a centrality class according to their elliptical anisotropies. By doing so, we gain an improved knowledge of the initial-state medium, consequently enabling better constraints on the average path length traversed by the jet. In these proceedings, new results of jet spectra from event-shape-engineered collisions at ALICE will be presented.