Light and Superlight Sterile Neutrinos in the Minimal Radiative Inverse Seesaw Model

TL;DR

This paper investigates light and superlight sterile neutrinos within a minimal radiative inverse seesaw model, proposing scenarios that explain neutrino oscillation anomalies, dark matter, and extra cosmic radiation through specific sterile neutrino mass and mixing configurations.

Contribution

It introduces novel benchmark scenarios with keV and eV-range sterile neutrinos, linking neutrino anomalies, dark matter, and cosmological observations within a unified minimal model.

Findings

KeV sterile neutrino as dark matter candidate with small active mixing.

eV-range sterile neutrinos explaining LSND, MiniBooNE, and reactor anomalies.

Superlight sterile neutrino potentially affecting future oscillation experiments and cosmology.

Abstract

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 LSND+MiniBooNE+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.