EQUIVALENCE OF RENORMALIZED COVARIANT AND LIGHT-FRONT PERTURBATION-THEORY - I - LONGITUDINAL DIVERGENCES IN THE YUKAWA MODEL

Light-front perturbation theory (LFPT) has been proposed as an alterna tive to covariant perturbation theory. LFPT is only acceptable if it p roduces invariant S-matrix elements. Doubts have been raised concernin g the equivalence of LFPT and covariant perturbation theory. The main obstacles to a rigorous proof of equivalence are algebraic complexity in the case of arbitrarily high orders in perturbation theory and the occurrence of longitudinal divergences not present in covariant pertur bation theory. We show in the case of the Yukawa model of fermions int eracting with scalar bosons at the one-loop level how to deal with the longitudinal divergences. Invariant S-matrix elements are obtained us ing our method.