Gauge invariant effective action for high-energy processes in QCD

The Born amplitudes for quasi-multi-Regge kinematics of produced gluons are constructed in accordance with the Feynman rules including apart from usual Yang-Mills vertices also an infinite number of induced vertices. The new vertices describe the interaction of physical gluons produced in direct channels with the reggeized gluons propagating in crossing channels. The nonlinear gauge invariant effective action reproducing these Feynman rules is constructed with the use of the Wilson contour integrals. After integrating over the physical degrees of freedom the reggeon action is derived.