NA64 uses the high-energy SPS muon beam to search for dark matter
The NA64 experiment started operations at CERN's SPS North Area in 2016. Its aim is to search for unknown particles from a hypothetical "dark sector." For these searches, NA64 directs an electron beam onto a fixed target. Researchers then look for unknown dark sector particles produced by collisions between the beam's electrons and the target's atomic nuclei.
Source: phys.org