Existence and Properties of Right‑Handed Neutrinos

Demonstrate the existence of right‑handed neutrinos (N1, N2, N3) and characterize their properties—such as masses, interactions, and possible roles in neutrino mass generation and leptogenesis—or establish stringent limits that exclude their participation at accessible scales.

Background

The discovery of neutrino masses motivates the introduction of right‑handed neutrinos, but their existence and properties remain unconfirmed. Establishing them would have major implications for the origin of neutrino masses (e.g., see‑saw mechanisms), sterile neutrino phenomenology, and baryogenesis via leptogenesis.

Clarifying whether right‑handed neutrinos exist is central to completing the lepton sector and to connecting laboratory neutrino physics with cosmology.