Effective action for quasielastic scatterings in QCD

A new effective action for the high energy quark-quark scatterings is obtained by applying a scaling approximation to the QCD action. The propagators are shown to factorize into the transverse and the longitudinal parts so that the scattering amplitudes are given in terms of the products of two-dimensional S matrices. We show that our action provides a natural effective field theory for Lipatov's theory of quark scatterings with quasielastic unitarity. The amplitude with quasielastic unitarity obtained from this action shows a ''Regge'' behavior and is eikonalized.