On p_T-broadening of high energy partons associated with the LPM effect in a finite-volume QCD medium

TL;DR

This paper investigates how radiation influences the transverse momentum broadening of high-energy partons in a finite QCD medium, highlighting significant corrections from the LPM effect and multiple scattering.

Contribution

It provides a detailed calculation of medium-induced gluon emission and self-energy diagrams, revealing large logarithmic corrections to p_T-broadening in perturbative QCD.

Findings

Double-logarithmic correction from incoherent scattering.

Logarithmic correction from the LPM effect.

Parametrically large radiation correction to p_T-broadening.

Abstract

We study the contributions from radiation to $p_{\perp}$-broadening of a high energy parton traversing a QCD medium with a finite length $L$. The interaction between the parton and the medium is described by decorrelated static multiple scattering. Amplitudes of medium-induced gluon emission and parton self-energy diagrams are evaluated in the soft gluon limit in the BDMPS formalism. We find both the double-logarithmic correction from incoherent scattering, which is parametrically the same as that in single scattering, and the logarithmic correction from the LPM effect. Therefore, we expect a parametrically large correction from radiation to the medium-induced $p_\perp$-broadening in perturbative QCD.