Search for invisible decays of sub-GeV dark photons in missing-energy events at the CERN SPS

NA64 Collaboration, D. Banerjee, V. Burtsev +44

We report on a direct search for sub-GeV dark photons (A') which might be produced in the reaction e^- Z \to e^- Z A' via kinetic mixing with photons by 100 GeV electrons incident…