New Fundamental Light Particle and Breakdown of Stefan-Boltzmann's Law
  Recently, we predicted the existence of fundamental particles in Nature, neutral Light Particles with spin 1 and rest mass $m=1.8\times 10^{-4} m_e$, in addition to electrons, neutrons and protons. We call these particles Light Bosons because they create electromagnetic field which represents Planck's gas of massless photons together with a gas of Light Particles in the condensate. Such reasoning leads to a breakdown of Stefan--Boltzmann's law at low temperature. On the other hand, the existence of new fundamental neutral Light Particles leads to correction of such physical concepts as Bose-Einstein condensation of photons, polaritons and exciton polaritons. 
V.N. Minasyan and V.N. Samoylov
physics.gen-ph