Type: Article
Publication Date: 2018-07-26
Citations: 54
DOI: https://doi.org/10.1103/physrevlett.121.041802
A novel mechanism to produce and detect light dark matter in experiments making use of GeV electrons (and positrons) impinging on a thick target (beam dump) is proposed. The positron-rich environment produced by the electromagnetic shower allows us to produce an ${A}^{\ensuremath{'}}$ via nonresonant (${e}^{+}+{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\gamma}+{A}^{\ensuremath{'}}$) and resonant (${e}^{+}+{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{A}^{\ensuremath{'}}$) annihilation on atomic electrons. The latter mechanism, for some selected kinematics, results in a larger sensitivity with respect to limits derived by the commonly used ${A}^{\ensuremath{'}}$-strahlung. This idea, applied to beam-dump experiments and active beam-dump experiments, pushes down the current limits by an order of magnitude.