| Popis: |
A quadrupole arrangement on a torsion pendulum of two polarized masses each having intrinsic spin ~ 1021h acts as a detector of hypothetical anomalous spin interactions. Unlike earlier experiments in our laboratories using local source masses acting on these detectors to investigate anomalous spin interactions, e.g. existence of the axion, this experiment seeks a possible anomalous spin sensing of matter on a scale as large as our galaxy. Rotation of the Earth provides a scan of the sky by the detector, and pendulum position variation is time-correlated with a predicted daily pattern. Our original motivation was the possibility of detecting an exotic dark matter cloud roughly centered in our galaxy, although other sources are conceivable. After eight years of essentially continuous operation, a long-term pattern has developed in the correlations of pendulum torque with predicted pattern. This is analyzed as an unspecified signal, and is referenced to a sidereal frame to separate it from from local noise and systematic causes. The expected high noise-to-signal level requires unusual analytical methods. A 1997 report at this School discussed results of the first two years of this experiment, which could not anticipate the 8-year pattern we now observe. |
