One-loop Lipatov vertex in QCD with higher $\epsilon$-accuracy

TL;DR

This paper computes the one-loop Lipatov vertex in QCD with higher epsilon-accuracy, crucial for advancing calculations in the BFKL approach at next-to-next-to-leading order.

Contribution

It provides the explicit expression for the one-loop Lipatov vertex in dimensional regularization up to order epsilon squared, enabling more precise high-order QCD calculations.

Findings

Derived the Lipatov vertex up to epsilon^2 order in dimensional regularization.

Facilitates next-to-next-to-leading order BFKL calculations in QCD.

Enhances the accuracy of theoretical predictions in high-energy QCD processes.

Abstract

The effective Reggeon-Reggeon-gluon vertex, known as Lipatov vertex, is the key ingredient that allows to develop the BFKL approach in QCD. Within the next-to-leading logarithmic approximation, it is sufficient to know its one-loop corrections, in dimensional regularization ($D=4+2\epsilon$), up to the constant term in the $\epsilon$-expansion. In the next-to-next-to-leading approximation, however, the one-loop Lipatov vertex is needed up to the order $\epsilon^2$. In this paper we present the expression for this vertex in dimensional regularization up to the required accuracy.