MAYFLOWER MINE 1500-GV DETECTOR - COSMIC-RAY ANISOTROPY AND SEARCH FOR CYGNUS-X-3

An underground muon detector was used to search for periodic changes in the cosmic-ray flux over a 5.4 yr period terminating in 1983 May. Primary cosmic rays with a median rigidity of 1.5 X 10(12) V produced a 4.4 Hz muon rate. The Fourier transformed data show a peak at the sidereal frequency with relative amplitude (3.2(-0.6)+0.8) x 10(-4), which after correction for solar motion with respect to the local interstellar medium indicates an anisotropy of (5.3(-0.7)+0.8) 10(-4) at R.A. 3.2h +/- 0.5h. We also observe a second harmonic with amplitude (2.9(-0.7)+0.9) x 10(-4) at alpha = 8.4h +/- 1.1h and a third harmonic with amplitude (2.1(-0.6)+0.8) x 10(-4) at alpha = 0.0h +/- 1.2h. These combine to produce a minimum when the detector "points" toward the north Galactic pole, and a broad maximum when its sensitive direction is close to the Galactic plane. The amplitude and phase of the signal at the solar frequency are those expected from the Earth's orbital motion. A search at the 5.01 day-1 Cyg X-3 frequency yields no robust signal.