One-loop Lipatov vertex in QCD with higher E-accuracy

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.

Automated summary

This paper presents the expression for the effective Reggeon-Reggeon-gluon vertex, known as the Lipatov vertex, in dimensional regularization up to the required accuracy for developing the BFKL approach in QCD. Its one-loop corrections are needed in the next-to-leading logarithmic approximation, and up to order epsilon(2) in the next-to-next-to-leading approximation.