The Factorisation of the t-channel Pole in Quark-Gluon Scattering

TL;DR

This paper explicitly demonstrates that the t-channel pole in quark-gluon scattering can be exactly factorized into local currents, improving the understanding of gluon scattering in collider physics.

Contribution

It provides a gauge-invariant definition of the t-channel current and clarifies the factorization properties of helicity amplitudes in quark-gluon scattering.

Findings

Only two helicity channels have non-pure t-channel pole contributions.

The t-channel pole can be exactly described as a contraction of two local currents.

The new gauge-invariant current improves gluon scattering predictions.

Abstract

By exploring the scattering of specific helicity states in quark-gluon scattering at tree level we show explicitly that the t-channel pole can be described exactly as a contraction of two local currents. Furthermore, we demonstrate that out of eight non-zero helicity possibilities, only two suppressed channels have contributions that are not pure, factorised t-channel poles. We thereby extract a gauge-invariant definition for the t-channel current generated by the scattering of a gluon. This offers a slight improvement in the description of gluon scattering in the framework of arXiv:0908.2786 for the prediction of n-jet rates at hadron colliders.