ONE-LOOP HELICITY AMPLITUDES FOR ALL 2-]2 PROCESSES IN QCD AND N=1 SUPERSYMMETRIC YANG-MILLS THEORY

One-loop corrections to the helicity amplitudes of all 2 --> 2 subproc esses are calculated in QCD and in N = 1 supersymmetric Yang-Mills the ory using two versions of dimensional regularization: the 't Hooft-Vel tman scheme and dimensional reduction. Studying the structure of the s oft and collinear singularities, we found universal transition rules f or the squared matrix element which can be used to translate the resul ts obtained in these schemes to the results valid in the conventional dimensional regularization scheme. With explicit calculation it is dem onstrated that the one-loop helicity amplitudes of the 2 --> 2 subproc esses calculated using dimensional reduction in the N = 1 supersymmetr ic SU(N) gauge theory respect the supersymmetry Ward identities. Our t ransition rules can also be used to calculate the next-to-leading orde r Altarelli-Parisi kernels in the dimensional reduction scheme when th ey satisfy supersymmetry Ward identities as well.