Abstract:
The famous Balitsky-Fadin-Kuraev-Lipatov (BFKL) equation was derived using the hypothesis that amplitudes of non-abelian gauge theories with the adjoint representation of the gauge group in cross-channels are given by the Reggeized gauge boson contributions. The hypothesis is true in the leading logarithmic approximation, wherein the equation was originally derived, and in the next-to-leading one. However, in the next-to-next-to-leading logarithmic approximation this is not so, since in this approximation the Regge cuts begin to contribute. Calculations of their contributions to elastic scattering amplitudes in quantum chromodynamics and their role in derivation of the BFKL equation are discussed.
This work was supported in part by the Ministry of Science and Higher Education of the Russian Federation and by the Russian Foundation for Basic Research, project no. 19-02-00690.