Elastic energy loss and longitudinal straggling of a hard jet

TL;DR

This paper investigates elastic energy loss and longitudinal momentum fluctuations of high-energy jets in nuclear media, introducing a new transport coefficient and computing its effects in quark-gluon plasma within the HTL approximation.

Contribution

It identifies a new transport coefficient $ ilde{e}$ for elastic energy loss and computes relevant operator products in a quark-gluon plasma, extending understanding of jet-medium interactions.

Findings

Introduction of a new transport coefficient $ ilde{e}$ for elastic energy loss.

Explicit calculation of operator products in a QGP using HTL approximation.

Analysis of longitudinal straggling effects on jet propagation.

Abstract

The elastic energy loss encountered by jets produced in deep-inelastic scattering (DIS) off a large nucleus is studied in the collinear limit. In close analogy to the case of (non-radiative) transverse momentum broadening, which is dependent on the medium transport coefficient $\hat{q}$, a class of medium enhanced higher twist operators which contribute to the non-radiative loss of the forward light-cone momentum of the jet ($q^-$) are identified and the leading correction in the limit of asymptotically high $q^-$ is isolated. Based on these operator products, a new transport coefficient $\hat{e}$ is motivated which quantifies the energy loss per unit length encountered by the hard jet. These operator products are then computed, explicitly, in the case of a similar hard jet traversing a deconfined quark-gluon-plasma (QGP) in the hard-thermal-loop (HTL) approximation. This is followed by an evaluation of sub-leading contributions which are suppressed by the light-cone momentum $q^-$, which yields the longitudinal "straggling" i.e., a slight change in light cone momentum due to the Brownian propagation through a medium with a fluctuating color field.