We report on 3.2 years live time of underground muon observations taken between 1981 and 1989 using the Soudan 1 proportional tube detector, located at a depth of 1,800 m water equivalent. The post-1984 observations are consistent with earlier published data on an excess signal apparently correlated with the Cygnus X-3 orbital period. The signal-to-background ratio in the entire data sample is 1 to 3 percent, depending on phase width. These data are not contradicted by other measurements. However, a larger detector will be required to establish a signal, if one exists, at a high level of certainty.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Nuclear and High Energy Physics