Regge Cuts and NNLLA BFKL

In the leading and next-to-leading logarithmic approximations, QCD amplitudes with gluon quantum numbers in cross-channels and negative signature have the pole form corresponding to a reggeized gluon. The famous BFKL equation was derived using this form. In the next-to-next-to-leading approximation (NNLLA), the pole form is violated by contributions of Regge cuts. We discuss these contributions and their impact on the derivation of the BFKL equation in the NNLLA.

Three-Reggeon cuts in QCD amplitudes

One of remarkable properties of QCD is the gluon Reggeization. The Reggeized gluon is the primary Reggeon in QCD; Pomeron and Odderon appear as compound states of the Reggeized gluons. Due to negative signature the Reggeized gluon gives the main contributions to high energy QCD amplitudes in each order ofperturbation theory. In the leading and next-to-leading logarithmic approximations these amplitudes aregiven by the Regge pole contributions. In the next-to-next-to-leading approximation the pole form of the amplitudes is violated by contributions of three-Reggeon cuts. We discuss these contributions to elastic QCD amplitudes.

On correlators of Reggeon fields and operators of Wilson lines in high energy QCD

In this paper we derive Dyson–Schwinger hierarchy of the equations for the correlators of reggeized gluon fields in the framework of Lipatov’s high energy QCD effective action formalism.[Formula: see text] The explicit perturbative expressions for the correlators till correlator of four Reggeon fields inclusively are obtained and different perturbative schemes for the solutions of the equation for the two-field correlator are discussed. A correspondence between the correlators of reggeized gluon fields and Wilson line operators of longitudinal gluon field is established with the help of the results of Ref. 10. The connection between the JIMWLK-Balitsky formalism and Lipatov’s effective action approach and applications of the obtained results are also discussed.

HIGH ENERGY FACTORIZATION AT NLO: LIPATOV'S EFFECTIVE ACTION REVISITED

We discuss aspects of our recent derivation of the gluon Regge trajectory at two loop from Lipatov's high energy effective action. We show how the gluon Regge trajectory can be rigorously defined through renormalization of the high energy divergence of the reggeized gluon propagator. We furthermore provide some details on the determination of the two-loop reggeized gluon self-energy.