WARD-TAKAHASHI IDENTITY ON THE LIGHT-FRONT

The Ward-Takahashi identity, reflecting local gauge invariance, is per turbatively verified for a boson model in light-front field theory. A careful integration over the light-front energy, corresponding to exac tly taking into account pair terms, which are the contributions of the zero longitudinal-momentum mode, is crucial to obtain this result. Fu rthermore, the one-loop boson form factors are calculated for arbitrar y off-shell momenta.