Projections for Dark Photon Searches at Mu3e

We show that dark photons (A0) with masses ~10-80MeV can be probed in the decay µ^+ → e^+v_ev_µA', A' → e^+e^-, with the upcoming Mu3e experiment at the Paul Scherrer Institute (PSI) in Switzerland. With an expected 10^(15)(5.5 x 10^(16)) muon decays in 2015{2016 (2018 and beyond), Mu3e has the exciting opportunity to probe a substantial fraction of currently unexplored dark photon parameter space, probing kinetic-mixing parameter, є, as low as є^2 10^(-7) (10^(-8)). No modifications of the existing Mu3e setup are required