Searched for long-lived dark photons decaying to hadronic lepton jets using the ATLAS detector

Abstract

Within the context of analyses looking for new particles in the ATLAS experiment at the Large Hadron Collider (LHC), a full event selection is designed to isolate simulated vector boson fusion (VBF) events where the Higgs boson decays to hadronic dark photon jet (hDPJ) signatures. Using this selection, a statistical significance of 4.2σ was obtained for a signal benchmark with a dark photon mass of 100 MeV, decay length 15 mm and electronic decay mode. Additionally, a lifetime reweighting method is implemented to allow for exclusion limit estimations as function of the dark photon proper decay length, given that all signal samples are generated with fixed dark photon lifetimes.