Origin of Neutrino Masses

Determine the physical origin of neutrino masses of the three active neutrinos inferred from oscillation data by identifying the mechanism that generates non-zero neutrino masses.

Background

Neutrino oscillation measurements establish that at least two neutrino mass eigenstates are non-zero, implying physics beyond the minimal Standard Model. Pinning down the mechanism that generates these masses remains a central challenge in particle physics.

This paper investigates phenomenology where ultralight scalar dark matter interacts with sterile neutrinos, inducing time- and redshift-dependent effective masses for active neutrinos via mixing. While these effects can modify cosmological and laboratory observables, the fundamental question of how neutrino masses originate remains an open problem motivating such studies.