  Electron proton (ep) colliders could provide particle collisions at TeV
energies with large data rates while maintaining the clean and pile~up-free
environment of lepton colliders, which makes them very attractive for heavy
neutrino searches. Heavy (mainly sterile) neutrinos with masses around the
electroweak scale are proposed in low scale seesaw models for neutrino mass
generation. In this paper, we analyse two of the most promising signatures of
heavy neutrinos at ep colliders, the lepton-flavour violating (LFV)
lepton-trijet signature and the displaced vertex signature. In the considered
benchmark model, we find that for heavy neutrino masses around a few hundred
GeV, the LFV lepton-trijet signature at ep colliders yields the best
sensitivity of all currently discussed heavy neutrino signatures (analysed at
the reconstructed level) up to now.
