Speaker
Description
In this talk, I will discuss an alternative production mechanism for long-lived heavy neutrinos within the framework of neutrinophilic Higgs doublet models, where an additional Higgs doublet couples exclusively to the Standard Model (SM) lepton doublets and right handed neutrinos (RHNs). This structure allows the vacuum expectation value (VEV) of the extra Higgs doublet to be much smaller than that of the SM Higgs, thereby generating naturally small Dirac neutrino masses without requiring extremely small Yukawa couplings. A distinctive feature of this framework is the presence of neutrinophilic charged Higgs bosons, which, once produced at the LHC through the Drell-Yan process, decay dominantly into heavy neutrinos and charged leptons. If the heavy neutrinos are sufficiently long-lived, their subsequent decays can give rise to displaced signatures at the LHC. Within the type-I seesaw framework with three RHNs, one of the heavy neutrinos can be long-lived even when it decays through on-shell gauge bosons. In this case, its lifetime is inversely proportional to the lightest neutrino mass while remaining consistent with neutrino oscillation data. I will discuss the displaced-vertex signatures of these long-lived heavy neutrinos produced from neutrinophilic charged Higgs decays at the High-Luminosity LHC. The talk is based on arXiv:2604.00866.
