On massless dyadic forms and no minimal coupling theorem
  We use the spinor helicity formalism in order to derive the dyadic forms for massless fields of various spins. We also give an iterated form of this approach in case higher spin theories are under study. This reduces calculations at hard and soft scattering problems in gauge theories drastically. Finally, we state and prove a theorem of gauge symmetry violation in the presence of minimal coupling with light in higher spin theories ($j>1/2$). 
Alexis Kassiteridis
hep-th