The Landau gauge and Feynman gauge differ by a term in the propagator for these particles, and that internal propagator has two spacetime indices.
The Landau gauge and Feynman gauge differ by a term in the propagator for these particles, and that internal propagator has two spacetime indices. Like gluons, these particles are on shell when their energy squared is equal to their momentum squared. In December ATLAS and CMS announced possible signs of a resonance at around 750 GeV which decays to two of these particles. A  virtual one of them is exchanged in both (*) Bhabha and Moller scattering. Electrons may be emitted when these particles' energy exceeds the work function, and they interact with electrons in Compton scattering. QED is the theory of their interactions with charged particles. These massless particles have energy equal to Planck's constant times their frequency. For 10 points, name this carrier of the electromagnetic force.
The Landau gauge and Feynman gauge differ by a term in the propagator for these particles, and that internal propagator has two spacetime indices.
photon