Virtual Next-to-Leading Corrections to the Lipatov Vertex
Vittorio Del Duca, Carl R. Schmidt
TL;DR
The paper computes the virtual next-to-leading corrections to the Lipatov vertex within the BFKL framework using a helicity-amplitude approach in multi-Regge kinematics. By analyzing the one-loop five-gluon amplitude, it extracts the dispersive parts that contribute to the Lipatov vertex, matches them to the reggeized ladder, and provides explicit expressions for the NLL corrections in both CDR/HV and dimensional-reduction schemes. It also obtains the soft-gluon corrections to all orders in ε and demonstrates the infrared and scheme consistency of the results. A key discussion centers on reggeization-scale dependence, proposing a running scale that eliminates problematic logs at NLL and clarifies how to maintain infrared cancellations at higher orders.
Abstract
We compute the virtual next-to-leading corrections to the Lipatov vertex in the helicity-amplitude formalism. These agree with previous results by Fadin and collaborators, in the conventional dimensional-regularization scheme. We discuss the choice of reggeization scale in order to minimize its impact on the next-to-leading-logarithmic corrections to the BFKL equation.