Vector Schwinger Model with a Photon Mass Term on the Light-Front
  Vector Schwinger model with a mass term for the photon, describing 2D electrodyn amics with massless fermions, studied by us recently, represents a new class of models. This theory becomes gauge-invariant when studied on the light-front. Thi s is in contrast to the instant-form theory which is gauge-noninvariant. We quan tize this theory on the light-front. 
Usha Kulshreshtha