The importance of multiple scatterings in medium-induced gluon radiation

TL;DR

This paper clarifies the physical mechanisms of medium-induced gluon radiation across different energy regimes, emphasizing the roles of single and multiple scatterings and their coherence effects.

Contribution

It provides a comprehensive comparison between a fully-resummed BDMPS-Z spectrum and analytical models, highlighting the importance of multiple scatterings and suppression factors.

Findings

High-energy radiation dominated by single hard scattering

Intermediate-energy regime requires coherence effects among multiple scatterings

Low-energy regime controlled by single scattering with suppression factor

Abstract

In this work we disentangle the underlying physical picture of the in-medium gluon radiation process across its different energy regimes by comparing the recently obtained fully-resummed -- without any further approximations -- BDMPS-Z in-medium emission spectrum with the extensively used analytical approaches. We observe that in the high-energy regime the radiation process is dominated by a single hard scattering, while in the intermediate-energy region coherence effects among multiple scatterings are crucial. Finally, we prove that in the low-energy regime the dynamics is again controlled by a single scattering but where one must include a suppression factor accounting for the probability of not having any further scatterings.