Abstract submitted to the 1999 Salt Lake City International Cosmic Ray Conference

Searches for the Cowan Effect -- A Peak at 21 hr LST for Mu-E-Decay Events

Abram Young, Patrick McGuire, and Theodore Bowen
Department of Physics, University of Arizona, Tucson, AZ 85721

In several 1960's experiments Clyde L. Cowan's group observed mu-e-decay events with a sharp, statistically-significant intensity peak near 21 hr LST (denoted the Cowan Effect). The zenith happened to be near 39 deg N and 21 hr RA, close to the direction (\sim 47 deg N, \sim 21 hr RA) of our galactic spiral arm and of the Sun's motion in the galaxy. 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 21 hr LST- -a huge Compton-Getting Effect for DM v/c \sim 1000. Peaks near 21 hr LST (presently \sim 2 to 3 \sigma) in low and high altitude Arizona experiments and in cosmic ray data from the LSND experiment (plus more new data) will be presented.

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