Figure 1

The neutrino mass spectrum, showing the usual solar and atmospheric mass differences, as well as the pseudo-Dirac splittings in each generation (though shown as equal, we assume they are independent). The active and sterile components of each pseudo-Dirac pair are ${\nu }_{ja}$ and ${\nu }_{js}$ and are maximal mixtures of the mass eigenstates ${\nu }_j^{+}$ and ${\nu }_j^{-}$. Neither the ordering of the active neutrino hierarchy nor the signs of the pseudo-Dirac splittings have any effect on our discussion.Reuse & Permissions

Figure 2

The ranges of distance and energy covered in various neutrino experiments. The diagonal lines indicate the mass-squared differences (in ${\mathrm{e}\mathrm{V}}^2$) that can be probed with vacuum oscillations; at a given $L/E$, larger $\delta m^2$ values can be probed by averaged oscillations. The shaded regions display the sensitivity of solar, atmospheric, reactor, supernova (SN), short-baseline (SBL), long-baseline (LBL), LSND [5], and extensive air shower (EAS) experiments. We focus on the KM3 region, which describes the parameter space that would be accessible to a $1\mathrm{\text{−}}{\mathrm{k}\mathrm{m}}^3$ scale neutrino telescope, given sufficient flux. Current neutrino flux estimates for extragalactic sources indicate that it will be a challenge for km-scale experiments to make a sensitive test of the scenario proposed here, and larger scale experiments would likely be necessary.Reuse & Permissions