BFKL Pomeron, Reggeized gluons and Bern-Dixon-Smirnov amplitudes

TL;DR

This paper reviews the BFKL approach to Regge processes in QCD and SUSY theories, proposes a method for calculating higher-order corrections, and examines the consistency of BDS amplitudes with BFKL predictions at high energies.

Contribution

It introduces a strategy for computing next-to-next-to-leading order BFKL kernel corrections and analyzes the analytic properties of BDS amplitudes for high-energy scattering.

Findings

Higher-order BFKL corrections can be expressed via Reggeized gluon cross-sections.

BDS amplitudes are inconsistent with BFKL predictions for more than five external particles beyond one loop.

Discrepancies suggest limitations of BDS ansatz in describing multi-particle high-energy amplitudes.

Abstract

After a brief review of the BFKL approach to Regge processes in QCD and in supersymmetric (SUSY) gauge theories we propose a strategy for calculating the next-to-next-to-leading order corrections to the BFKL kernel. They can be obtained in terms of various cross-sections for Reggeized gluon interactions. The corresponding amplitudes can be calculated in the framework of the effective action for high energy scattering. In the case of N=4 SUSY it is also possible to use the Bern-Dixon-Smirnov (BDS) ansatz. For this purpose the analytic properties of the BDS amplitudes at high energies are investigated, in order to verify their self-consistency. It is found that, for the number of external particles being larger than five, these amplitudes, beyond one loop, are not in agreement with the BFKL approach which predicts the existence of Regge cuts in some physical channels.