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

摘要

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 (NA64 mu) 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 x 10(12) electrons on target (EOT) NA64e is able to probe the scalar and Majorana LDM scenarios, the combined NA64e and NA64 mu results with similar or equal to 10(13) EOT and a few 10(13) MOT, respectively, will allow covering significant region in the parameter space of the most interesting LDM models. This makes NA64e and NA64 mu extremely complementary to each other and increases significantly the discovery potential of sub-GeV DM. (C) 2019 The Authors. Published by Elsevier B.V.