Hierarchical Four-Neutrino Oscillations With a Decay Option

We present a new and novel synthesis of all existing neutrino data regarding the disappearance and appearance of $\nu_e$ and $\nu_\mu$. We assume four neutrinos: $\nu_e, \nu_\mu, \nu_\tau$, as well as a heavier singlet neutrino $\nu_s$ of a few eV. The latter may decay into a massless Goldstone boson (the singlet Majoron) and a linear combination of the doublet antineutrinos. We comment on how this scenario may be verified or falsified in future experiments.