Neutrino decay and spontaneous violation of lepton number

摘要: The orders of magnitude decay rates for relatively light neutrinos are studied in the framework SU(2)\ifmmode\times\else\texttimes\fi{}U(1) gauge group. assumption is made that a hierarchy parameter $\ensuremath{\epsilon}(\ensuremath{\approx}(\mathrm{muon}\mathrm{mass})\textdiv{}[\mathrm{some}\mathrm{new}\mathrm{mass}\mathrm{scale}(\mathrm{possibly}\mathrm{much}\mathrm{smaller}\mathrm{than}\mathrm{the}\mathrm{grand}\mathrm{unification}\mathrm{scale})])$ plays meaningful role full theory. For orientation it first noted traditional $\ensuremath{\nu}\ensuremath{\gamma}$ channel as well $3\ensuremath{\nu}$ give neutrino lifetimes which "typical" parameters substantially longer than age universe. Then we examine detail some recent proposals claimed to result greatly speeded-up decays into $\ensuremath{\nu}$+Majoron, where Majoron true Goldstone boson associated with spontaneous breakdown lepton number. In theory usual Higgs doublet augmented by complex singlet (1-2 model) width $\ensuremath{\nu}$+Majoron actually vanishes order ${\ensuremath{\epsilon}}^{5}$. triplet (2-3 this shown vanish exactly, neglecting radiative corrections. A more general (1-2-3 constructed and also yield vanishing tree-level rate Finally, tree amplitudes 1-2 1-2-3 models widths ${\ensuremath{\epsilon}}^{9}$ correspond much greater