Abram Young, Patrick McGuire, Theodore Bowen
University of Arizona Physics
In several 1960's experiments Clyde Cowan's group observed mu-e-decay events with a sharp, statistically-significant intensity peak near 21hrLST. The mu-e-decay detectors were omnidirectional, but the response would be strongly peaked at the zenith if the atmosphere highly attenuated the primary particles. If galactic dark matter (DM) includes a nonrotating, strongly-interacting component (SIMPs), it would arrive at Earth as a highly directional "wind," peaking at 21hrLST- -a huge Compton-Getting Effect for DM v/c~1/1000. Current data puts an excess at 21hr LST (presently 4.8 sigma) in high altitude Arizona stopping muon experiments. A dark-matter (DM) hypothesis is proposed to explain the excess and a model presented in which the slowly-moving, neutral SIMPs are captured by N and O nuclei, emitting at least one pion or kaon which decays into a muon.