Determine masses, multiplicity, and interaction strengths of right-handed sterile neutrinos

Determine the masses, the number of species (multiplicity), and the interaction strengths of right-handed sterile neutrinos introduced to augment the Standard Model to account for observed neutrino masses, quantifying these properties in light of current experimental and observational constraints.

Background

Neutrino oscillations imply nonzero neutrino masses, which the Standard Model does not accommodate without extension. A common approach is to introduce right-handed sterile neutrinos. However, their fundamental properties—including how many species exist, their mass scales, and their interaction strengths—are not fixed by current data.

This paper studies constraints on a specific interaction channel, the active–sterile transition magnetic moment (dipole portal), using supernova observations. While deriving new bounds, the authors explicitly note the broader uncertainty surrounding the fundamental properties of sterile neutrinos, highlighting a central open question in the field.