Resolvable heavy neutrino-antineutrino oscillations at colliders

Heavy neutrino-antineutrino oscillations can naturally appear in mechanisms of low scale neutrino mass generation, where pairs of heavy neutrinos have almost degenerate masses. We discuss the case where the heavy neutrinos are sufficiently long-lived to decay displaced from the primary vertex, such that the oscillations of the heavy neutrinos into antineutrinos can potentially be observed at the (high-luminosity) LHC and at currently planned future collider experiments. The observation of these oscillations would have far-reaching consequences: it would, for instance, prove the existence of lepton number violation and the Majorana nature of neutrino masses, and it would allow a deep insight into the nature of the neutrino mass generation mechanism.