Combined search for light dark matter with electron and muon beams at NA64

• Main Authors: S.N. Gninenko, D.V. Kirpichnikov, M.M. Kirsanov, N.V. Krasnikov
• Format: Article
• Language: English
• Published: Elsevier 2019-09-01
• Series: Physics Letters B
• Online Access: http://www.sciencedirect.com/science/article/pii/S037026931930471X

We discuss prospects of searching for a dark photon (A′) which serves as mediator between Standard model (SM) particles and light dark matter (LDM) by using the combined results from the NA64 experiment at the CERN SPS running in high-energy electron (NA64e) and muon (NA64μ) modes. We discuss the most natural values and upper bounds on the A′ coupling constant to LDM and show they are lying in the range accessible at NA64. While for the projected 5×1012 electrons on target (EOT) NA64e is able to probe the scalar and Majorana LDM scenarios, the combined NA64e and NA64μ results with ≃1013 EOT and a few 1013 MOT, respectively, will allow covering significant region in the parameter space of the most interesting LDM models. This makes NA64e and NA64μ extremely complementary to each other and increases significantly the discovery potential of sub-GeV DM.