Jet quenching and its substructure dependence due to color decoherence

TL;DR

This paper develops a theoretical framework combining vacuum-like and medium-induced emissions to study jet quenching and substructure dependence in heavy-ion collisions, successfully describing experimental data.

Contribution

It introduces a novel model integrating vacuum evolution and medium effects, accounting for jet substructure and cone size dependence in jet quenching phenomena.

Findings

Accurately describes the inclusive jet modification factor $R_{AA}$ for large-radius jets.

Reproduces the dependence of jet quenching on substructure in PbPb collisions.

Provides insights into color decoherence effects in the QCD medium.

Abstract

Motivated by color coherence and decoherence effects in the QCD medium, we propose a theoretical framework that combines vacuum-like emissions and medium-induced radiation to study jet quenching and its dependence on jet cone sizes and substructure. In our approach, a jet produced at a hard scale $Q$ first undergoes vacuum-like evolution, as described by the well-established generating-function method in the double logarithmic approximation. These vacuum-like emissions generate subjets at an infrared momentum scale $Q_0$. Each subjet then experiences medium-induced energy loss as described by the BDMPS-Z formalism. By modeling the QCD bulk medium using OSU (2+1)-dimensional viscous hydrodynamics and treating $Q_0$ together with the jet-quenching parameters at the initial proper time of the hydrodynamic evolution as free parameters, our approach provides a very good description of the inclusive jet modification factor $R_{AA}$ for large-radius jets and its dependence on jet substructure in 0-10% PbPb collisions at $\sqrt{s_{NN}} = 5.02~\rm{TeV}$, as measured by the ATLAS experiment.