Novel SM-like Higgs decay into displaced heavy neutrino pairs in U(1)′ models

A bstract We examine the observability of heavy neutrino ( ν h ) signatures of a U(1)′ enlarged Standard Model (SM) encompassing three heavy Majorana neutrinos alongside the known light neutrino states at the the Large Hadron Collider (LHC). We show that heavy neutrinos can be rather long-lived particles producing distinctive displaced vertices that can be accessed in the CERN LHC detectors. We concentrate here on the gluon fusion production mechanism gg → H 1,2 → ν h ν h , where H 1 is the discovered SM-like Higgs and H 2 is a heavier state, yielding displaced leptons following ν h decays into weak gauge bosons. Using data collected by the end of the LHC Run 2, these signatures would prove to be accessible with negligibly small background.