Stars as Laboratories for Fundamental Physics - MPP Theory Group

Solar Neutrinos 375
Fig. 10.16. 37 Ar production rate at Homestake, integral number of sunspots,
and neutron counts at McMurdo (Antarctica) which are indicative of the
primary cosmic-ray proton flux above 0.4 GeV; annual bins each. In the
center panel, the number of the solar cycle is also indicated. (Adapted from
Bieber et al. 1990.)
man rank-order correlation coefficient and Kendall’s tau (e.g. Press
et al. 1986). They found a moderate statistical significance level of
1.3% (Spearman) and 0.9% (Kendall) for the argon-production rate to
be correlated with the sunspot index. 56
Most recently, a correlation between the 1970−1991 argon production
rate and the solar activity cycle was investigated by Oakley et al.
(1994). They used the Mt. Wilson 150-ft. tower magnetograms as an
indicator for the solar magnetic surface flux, both for the full solar disk
56 The significance level gives approximately the probability that a random shuffling
of the data gives an equally good or better (anti)correlation. A significance
level smaller than 1% is considered “highly significant.”