We propose an inclusive search for dark photons A' at the LHCb experiment based on both prompt and displaced di-muon resonances.
Because the couplings of the dark photon are inherited from the photon via kinetic mixing, the dark photon A' -> mu+mu- rate can be directly inferred from the off-shell photon gamma* -> mu+mu- rate, making this a fully data-driven search. For Run 3 of the LHC, we estimate that LHCb will have sensitivity to large regions of the unexplored dark-photon parameter space, especially in the 210-520 MeV and 10-40 GeV mass ranges. This search leverages the excellent invariant-mass and vertex resolution of LHCb, along with its unique particle-identification and real-time data-analysis capabilities.
