Searches for light sterile neutrinos with multitrack displaced vertices

Abstract

We study discovery prospects for long-lived sterile neutrinos at the LHC with multitrack displaced vertices, with masses below the electroweak scale. We reinterpret current displaced vertex searches making use of publicly available, parametrized selection efficiencies for modeling the detector response to displaced vertices. We focus on production of right-handed $W_{R}$ bosons and neutrinos $N$ in a left-right symmetric model, and find poor sensitivity. After proposing a different trigger strategy (considering the prompt lepton accompanying the neutrino displaced vertex) and optimized cuts in the invariant mass and track multiplicity of the vertex, we find that the LHC with $\sqrt{s}=13$ TeV and 300 fb$^{-1}$ is able to probe sterile neutrino masses between $10\hspace{0.1cm}\mbox{GeV}<m_{N}<20$ GeV (for a right-handed gauge boson mass of $2\hspace{0.1cm}\mbox{TeV}<m_{W_{R}}<3.5$ TeV). To probe higher masses up to $m_{N}\sim 30$ GeV and $m_{W_{R}}<5$ TeV, 3000 fb$^{-1}$ will be needed. This work joins other efforts in motivating dedicated experimental searches to target this low sterile neutrino mass region.