Jet energy loss and fragmentation in heavy ion collisions

TL;DR

This paper uses a simplified model to explain the observed suppression of jet fragmentation functions in heavy ion collisions, reconciling experimental data with QCD radiation theories.

Contribution

It introduces an effective 1+1 dimensional model that successfully describes jet fragmentation modifications in the medium, aligning with LHC observations.

Findings

Model reproduces the suppression of fragmentation functions at intermediate .

Partial color charge screening by medium-induced gluons explains the suppression.

No contradiction between experimental results and QCD radiation picture.

Abstract

Recent LHC results indicate a suppression of jet fragmentation functions in Pb-Pb collisions at intermediate values of $\xi=\ln(1/z)$. This seems to contradict the picture of energy loss based on the induced QCD radiation that is expected to lead to the enhancement of in-medium fragmentation functions. We use an effective 1+1 dimensional quasi-Abelian model to describe the dynamical modification of jet fragmentation in the medium. We find that this approach describes the data, and argue that there is no contradiction between the LHC results and the picture of QCD radiation induced by the in-medium scattering of the jet. The physics that underlies the suppression of the in-medium fragmentation function at intermediate values of $\xi=\ln(1/z)$ is the partial screening of the color charge of the jet by the comoving medium-induced gluon.