Paper detail

Pseudo-Dirac neutrinos via mirror-world and depletion of UHE neutrinos

We propose a possible particle physics explanation of the non-observation of muon neutrino events at IceCube coincident with GRB gamma ray at the rates predicted by the standard Bahcall-Waxman model, in terms of neutrino oscillations. Our model is based on assuming that (a) all neutrinos are pseudo-Dirac particles and (b) there exists a mirror world interacting gravitationally with the observed world. This scenario has three sterile neutrinos associated with each flavour of ordinary neutrinos. Very tiny mass splitting between these neutrinos is assumed to arise from lepton number violating dimension five operators suppressed by the Planck scale. We show that if a mass splitting of 10^(-15) eV^2 is induced between the four mass eigenstates of a given species, then its flux will be suppressed at IceCube energies by a factor of 4 which could be the explanation of the IceCube observation that the muon neutrino flux is lower than expected. Hierarchies in mass splitting among different flavours may result in different amount of suppression of each flavour and based on this, we predict a difference in the flavour ratios of the observed neutrinos which is significantly different compared to the standard prediction of nu_e:nu_mu:nu_tau=1:1:1 which could serve as a test for this model.