Quantum field theory in the limit x<<1

The asymptotic high momentum behavior of quantum field theories with cubic interactions is investigated using renormalization group techniques in the asymmetric limit x much less than 1. Particular emphasis is paid to theories with interactions involving more than one field where it is found that a matrix renormalization is necessary. Asymptotic scaling forms, in agreement with Regge theory, are derived for the elastic two-particle scattering amplitude and verified in one-loop renormalization group improved perturbation theory, corresponding to the summation of leading logs to all orders. We give explicit forms for the Regge trajectories of different scalar theories in this approximation and determine the signatures.