Recent results in the BFKL theory
A. Papa
TL;DR
This paper surveys the BFKL approach to high-energy perturbative QCD, focusing on gluon Reggeization as the backbone of the formalism. It contrasts the leading-logarithmic (LLA) and next-to-leading (NLA) formulations, detailing how the BFKL equation emerges from s-channel unitarity and multi-Regge kinematics, and how Reggeized gluons govern both elastic and inelastic amplitudes. It discusses the large NLA corrections, the status of bootstrap consistency checks, and the role of impact factors and kernel structure in achieving a reliable description. The introduction of strong bootstrap criteria provides additional, albeit partial, consistency checks that relate octet impact factors, kernel eigenfunctions, and Regge trajectories, shaping ongoing assessments of the framework's validity and scope.
Abstract
The Balitsky-Fadin-Kuraev-Lipatov (BFKL) approach for the cross sections at high energy $\sqrt s$ in perturbative QCD is briefly reviewed. The role of gluon Reggeization in the derivation of the BFKL equation and its compatibility with $s$-channel unitarity (``bootstrap'') are discussed.