Probing Jet-Medium Interactions in Heavy-Ion Collisions Using Energy-Energy Correlators

TL;DR

This paper introduces a new method using energy-energy correlators and momentum conservation to probe jet-medium interactions in heavy-ion collisions, improving the understanding of jet quenching effects.

Contribution

We develop an augmentation technique exploiting momentum conservation in gamma-jet events to better reconstruct EECs and study jet-medium interactions in heavy-ion collisions.

Findings

The augmented EEC shows better agreement with jet hadron origins.

Comparing EECs in Pb+Pb and p+p collisions reveals sensitivity to jet-medium interactions.

The method provides a new way to test jet energy loss scenarios in QGP.

Abstract

Energy-energy correlators (EECs) provide a sensitive probe of both perturbative and nonperturbative dynamics in relativistic heavy-ion collisions. Jet-medium interactions enhance particle multiplicity within the jet cone, which must be properly accounted for when extracting the EEC of jet shower hadrons in experiments. To address this issue, we develop an augmentation method that exploits momentum conservation between the near-side and away-side regions, using $\gamma$-jet events with 0-10\% centrality in Pb+Pb collisions at $\sqrt{s_{NN}} = 5.02$ TeV simulated with the CoLBT-hydro model. This approach yields an experimentally reconstructed EEC that shows improved agreement with the EEC of hadrons originating primarily from jet parton splittings. Comparing EECs of jets from Pb+Pb and p+p collisions with different matching conditions can be sensitive to jet medium interaction dynamics, and provide a novel means to test the scenario of jet energy loss in the QGP, followed by fragmentations outside the QGP.