Improved limits on a hypothetical X(16.7) boson and a dark photon decaying into $e^{+}{e}^{-}$ pairs

D. Banerjee, J. Bernhard, V. E. Burtsev +51

The improved results on a direct search for a new X(16.7 MeV) boson which could explain the anomalous excess of $e^{+}{e}^{-}$ pairs observed in the excited 8Be nucleus decays ("Berilliu…