Strong Supernova 1987A Constraints on Bosons Decaying to Neutrinos
Damiano F. G. Fiorillo, Georg G. Raffelt, Edoardo Vitagliano
Abstract
Majoron-like bosons would emerge from a supernova (SN) core by neutrino coalescence of the form $\ensuremath{\nu}\ensuremath{\nu}\ensuremath{\rightarrow}\ensuremath{\phi}$ and $\overline{\ensuremath{\nu}}\overline{\ensuremath{\nu}}\ensuremath{\rightarrow}\ensuremath{\phi}$ with 100-MeV-range energies. Subsequent decays to (anti)neutrinos of all flavors provide a flux component with energies much larger than the usual flux from the ``neutrino sphere.'' The absence of 100-MeV-range events in the Kamiokande-II and Irvine-Michigan-Brookhaven signal of SN 1987A implies that less than 1% of the total energy was thus emitted and provides the strongest constraint on the Majoron-neutrino coupling of $g\ensuremath{\lesssim}{10}^{\ensuremath{-}9}\text{ }\text{ }\mathrm{MeV}/{m}_{\ensuremath{\phi}}$ for $100\text{ }\text{ }\mathrm{eV}\ensuremath{\lesssim}{m}_{\ensuremath{\phi}}\ensuremath{\lesssim}100\text{ }\text{ }\mathrm{MeV}$. It is straightforward to extend our new argument to other hypothetical feebly interacting particles.