Medium-induced fragmentation and equilibration of highly energetic partons

TL;DR

This paper models the in-medium evolution of high-energy jets in QCD, revealing that radiative processes dominate energy loss through an inverse cascade, affecting jet fragmentation and equilibration.

Contribution

It introduces an effective kinetic framework including elastic and radiative processes, accounting for back-reaction, to describe jet evolution from high to medium energy scales.

Findings

Energy loss mainly via inverse turbulent cascade from radiative branchings.

Elastic processes and back-reaction are crucial for soft fragment equilibration.

Jet energy spectra are significantly influenced by radiative cascades.

Abstract

We investigate the energy loss and equilibration of highly energetic particles/jets inside a QCD medium. Based on an effective kinetic description of QCD, including $2\leftrightarrow 2$ elastic processes, radiative $1\leftrightarrow 2$ processes, as well as the back-reaction of jet constituents onto the thermal medium, we describe the in-medium evolution of jets from the energy scale of the jet $\sim E$ all the way to the medium scale $\sim T $. While elastic processes and back-reaction are important to describe the equilibration of soft fragments of the jet, we find that the energy loss is dominated by an inverse turbulent cascade due to successive radiative branchings, which has interesting implications for the energy spectra and chemistry of jet fragments.