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arXiv · hep-ex/9905043

Cosmic Ray Sun Shadow in Soudan 2 Underground Muon Flux

Soudan 2 Collaboration
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Abstract

The absorption of cosmic rays by the sun produces a shadow at the earth. The angular offset and broadening of the shadow are determined by the magnitude and structure of the interplanetary magnetic field (IPMF) in the inner solar system. We report the first measurement of the solar cosmic ray shadow by detection of deep underground muon flux in observations made during the entire ten-year interval 1989 to 1998. The sun shadow varies significantly during this time, with a $3.3σ$ shadow observed during the years 1995 to 1998.

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Soudan 2 Collaboration. 1999-05-24. Cosmic Ray Sun Shadow in Soudan 2 Underground Muon Flux. https://arxiv.org/abs/hep-ex/9905043

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