Dark photon production through positron annihilation in beam-dump experiments
Dark photon production through positron annihilation in beam-dump experiments
High-energy positron annihilation is a viable mechanism to produce dark photons (${A}^{\ensuremath{'}}$). This reaction plays a significant role in beam-dump experiments using multi-GeV electron beams on thick targets by enhancing the sensitivity to ${A}^{\ensuremath{'}}$ production. The positrons produced by the electromagnetic shower can produce an ${A}^{\ensuremath{'}}$ via nonresonant (${e}^{+}+{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\gamma}+{A}^{\ensuremath{'}}$) and …