GAUGE-MODEL FOR THE EXCESS COSMIC MICROWAVE BACKGROUND

We point out that the radiative-neutrino-decay mechanism proposed by Fukugita to explain the observed excess microwave background radiation can be naturally realized in a class of gauge models, where the primary decay mode of the heavy neutrino is 3e with a radiative branching ratio BH10-410-5. These models also provide a natural understanding of the smallness of the neutrino masses via the seesaw mechanism. Constraints from muon-decay experiments require the existence of a light Higgs particle with MH below 100 GeV which couples dominantly to the neutrinos. © 1990 The American Physical Society.