  Heavy neutral leptons are present in many well-motivated beyond the Standard
Model theories, sometimes being accessible at present colliders. Depending on
their masses and couplings they could be long-lived and lead to events with
displaced vertices, and thus to promising signatures due to low Standard Model
background. We revisit the potential of the LHC to discover this kind of new
particles via searches for displaced vertices, which can probe masses of few
GeV for mixings currently allowed by experimental constraints. We also discuss
the importance of considering all the possible production channels, including
the production in association with light neutrinos, in order to fully explore
this region of the parameter space.
