Limit on leptonic photon interactions from SN1987a

If massless leptonic photons associated to electron, muon or tau leptonic number exist they would have been emitted from supernova 1987a via the annihilation process νν → γlγl. By requiring that this process does not carry away most of the energy that can be radiated by the supernova we obtain an upper limit on the leptonic photon coupling constants, αl < 1.6 × 10−11. Under certain assumptions about γl - trapping conditions we find that the region of αl = 10−8 – 10−7 might be of interest for an experimental search for leptonic photons.