Bremsstrahlung process ντ→νee+e- γ -: art. no. 113004

The bremsstrahlung process nu(tau)-->nu(e)e(+)e(-) gamma is the dominant photon-producing decay of heavy tau neutrinos with m(nu tau) >2m(e) so that this process is instrumental for supernova 1987A constraints on the properties of these particles, notably on their mixing amplitude with nu(e). We calculate the rate of the bremsstrahlung process as well as the photon spectrum and the angular distribution relative to the spin direction of the parent neutrino. We carefully pay attention to the difference between Dirac and Majorana neutrinos. [S0556-2821(98)05517-9].