Implementation of the Leibbrandt-Mandelstam gauge prescription in the null-plane bound-state equation

In gauge theories in a null-plane gauge, infinities can arise from the 1/n·q singularity in the gauge boson propagator. Liebbrandt and Mandelstam have given a prescription for defining this singularity so as to give finite results for the four-dimensional loop integrals in Feynman diagrams. However, this prescription is not directly applicable to calculations based on x+ ordered perturbation theory, and in particular to the null-plane bound-state equation. We show how the prescription can be applied in the simplest version of this kind of calculation