We explore the possibility of light and superlight sterile neutrinos in the recently proposed minimal radiative inverse seesaw extension of the Standard Model for neutrino masses, in which all existing neutrino data can be explained. In particular, we discuss two benchmark scenarios with one of the three sterile neutrino states in the keV range, having very small mixing with the active neutrinos to account for the dark matter in the Universe, while (i) the other two light sterile neutrino states could be in the eV range, possessing a nonzero mixing with the active states as required to explain the $\mathrm{LSND}+\mathrm{MiniBooNE}+\mathrm{\text{reactor}}$ neutrino data, or (ii) one of the light sterile states is in the eV range, whereas the second one could be superlight and almost mass-degenerate with the solar neutrinos. Such superlight sterile neutrinos could give rise to potentially observable effects in future neutrino oscillation experiments and may also offer a possible explanation for the extra radiation observed in the Universe.

• Received 24 December 2012

DOI:https://doi.org/10.1103/PhysRevD.87.053007