Lorentz-violating photons with a mass term
  Perturbative calculations in quantum field theory often require the regularization of infrared divergences. In quantum electrodynamics, such a regularization can for example be accomplished by a photon mass introduced via the Stueckelberg method. The present work extends this method to the QED limit of the Lorentz- and CPT-violating Standard-Model Extension. 
Mauro Cambiaso, Ralf Lehnert, Robertus Potting
hep-ph