One-loop impact factor for the emission of two gluons

TL;DR

This paper computes the one-loop impact factor for two-gluon emission in QCD within next-to-multi-Regge kinematics, advancing precision in gluon-jet impact factor calculations at NNLO accuracy.

Contribution

It presents the first calculation of loop-level QCD amplitudes in next-to-multi-Regge kinematics with a novel reggeisation approach for each colour-ordered amplitude.

Findings

Provides the last missing ingredient for NNLO gluon-jet impact factor.

Introduces a new reggeisation ansatz for loop amplitudes in complex kinematics.

Enables more precise theoretical predictions in high-energy QCD processes.

Abstract

We consider one-loop five-point QCD amplitudes in next-to-multi-Regge kinematics, and evaluate the one-loop impact factor for the emission of two gluons. This is the last ingredient which is necessary to evaluate the gluon-jet impact factor at NNLO accuracy in $\as$. It is also the first instance in which loop-level QCD amplitudes are evaluated in next-to-multi-Regge kinematics, which requires to apply a different reggeisation ansatz to each colour-ordered amplitude.