Comment on the paper "Energy Loss of Charm Quarks in the Quark-Gluon Plasma : Collisional vs Radiative"

TL;DR

This paper critically examines the methods and results of a previous study on charm quark energy loss in quark-gluon plasma, highlighting issues with its conceptual and numerical reliability, especially in the massless approximation.

Contribution

It provides a critical analysis of prior calculations on charm quark energy loss, questioning their reliability and offering clarifications on the massless case.

Findings

Identifies conceptual flaws in previous energy loss estimates.

Highlights numerical inaccuracies in earlier results.

Focuses on the limitations of the massless approximation.

Abstract

In the article by M. G. Mustafa published in Phys. Rev. C {\bf 72}, 014905 (2005) the author has estimated the total energy loss of a charm quark and quenching of hadron spectra due to the collisional energy loss of energetic partons in an expanding quark-gluon plasma employing Fokker-Planck equation. We wish to point out through this Comment that some of conceptual and numerical results of the said paper are unreliable. For the sake of clarity our discussion will focus on the massless case (although a few remarks on the $m\neq 0$ case are also made).