Displaced heavy neutrinos from Z′ decays at the LHC

We study the LHC sensitivity to probe a long-lived heavy neutrino N in the context of Z′ models. We focus on displaced vertex signatures of N when pair produced via a Z′, decaying to leptons and jets inside the inner trackers of the LHC experiments. We explore the LHC reach with current long-lived particle search strategies for either one or two displaced vertices in association with hadronic tracks or jets. We focus on two well-motivated models, namely, the minimal U(1)B−L scenario and its U(1)X extension. We find that searches for at least one displaced vertex can cover a significant portion of the parameter space, with light-heavy neutrino mixings as low as |VlN|2≈ 10−17, and l = e, μ accessible across GeV scale heavy neutrino masses.