Efficiency of the CMS detector for dark photons decaying to opposite sign muon or electron pairs

Dark sector photons with GeV scale masses could decay to opposite-sign standard model lepton pairs. If the dark photon originates from a heavy particle, for example a BSM Higgs, the dark photon is boosted in the lab frame resulting in decay products in a narrow angular cone containing a lepton pair referred to as a "lepton jet". In several production models, the dark photons are produced in pairs, resulting in events with two lepton jets. Using the Pythia event generator with a full simulation of the CMS detector, the detection efficiency is studied for dark photon decays to opposite sign muon or electron pairs.