Abstract

We study the LHC discovery potential in the search for heavy neutral leptons (HNL) with a new signature: a displaced shower in the CMS muon detector, giving rise to a large cluster of hits forming a displaced shower. A new Delphes module is used to model the CMS detector response for such displaced decays. We reinterpret a dedicated CMS search for neutral long-lived particles decaying in the CMS muon endcap detectors for the minimal HNL scenario. We demonstrate that this new strategy is particularly sensitive to active-sterile mixings with ? leptons, due to hadronic ? decays. HNL masses between ~ 1–6 GeV can be accessed for mixings as low as |V?N|2~10?7, probing unique regions of parameter space in the ? sector. © 2023, The Author(s).