Gluon Regge trajectory at two loops from Lipatov's high energy effective action

Understand

We present the derivation of the two-loop gluon Regge trajectory using Lipatov's high energy effective action and a direct evaluation of Feynman diagrams.

• Using a gauge invariant regularization of high energy divergences by deforming the light-cone vectors of the effective action, we determine the two-loop self-energy of the reggeized gluon, after computing the master integrals involved using the Mellin-Barnes representations technique.
• The self-energy is further matched to QCD through a recently proposed subtraction prescription.
• The Regge trajectory of the gluon is then defined through renormalization of the reggeized gluon propagator with respect to high energy divergences.