Gluon emission in Quark-Gluon Plasma

TL;DR

This paper develops a formalism to calculate gluon emission amplitudes in quark-gluon plasma, introducing a new dynamical scale and a universal emission function to simplify energy loss computations.

Contribution

It presents a novel solution for gluon emission amplitudes including LPM effects and defines a universal emission function g(x) for different processes.

Findings

Gluon emission amplitude F(h,p,k) obtained via iterative solution.

A new dynamical scale x for gluon emission introduced.

Universal emission function g(x) defined for multiple processes.

Abstract

Gluon radiation is an important mechanism for parton energy loss as the parton traverses the quark gluon plasma (QGP) medium. We studied the gluon emission in QGP using AMY formalism. In the present work, we obtained gluon emission amplitude {\bf F}({\bf h},p,k) function, which is a solution of the integral equations describing gluon radiation including Landau-Pomeranchuk-Migdal (LPM) effects, using iterations method. We define a new dynamical scale for gluon emission denoted by $x$. The gluon emission rate is obtained by integrating these amplitude function over {\bf h}. We show that these obey a simple scaling in terms of this dynamical variable $x$. We define the gluon emission function $g(x)$ for gluon radiation for the three processes $g\rightarrow gg$, $q\rightarrow gq$ and $g\rightarrow q\bar{q}$. In terms of this $g(x)$ function, the parton energy loss calculations, due to medium induced gluon radiation, may become simplified.