Stars as Laboratories for Fundamental Physics - MPP Theory Group

386 Chapter 10
Fig. 10.19. Allowed range of neutrino masses and mixing angles in the neutrino
experiments if the flux deficit relative to the Bahcall and Pinsonneault
(1995) solar model is interpreted in terms of neutrino oscillations. The experimental
data include all summarized in Sect. 10.3. (Plot adapted from
Hata and Haxton 1995.)
is rather stable against variations of S 17 (Krastev and Smirnov 1994;
Berezinsky, Fiorentini, and Lissia 1994).
Another approach is to allow S 17 to float freely when performing a
maximum-likelihood analysis, i.e. to fit it simultaneously with the neutrino
parameters from all solar neutrino experiments (Hata and Langacker
1994). The best-fit value is found to be 1.43 +0.65
−0.42 times the standard
22.4 eV b. Of course, the 95% CL range for the best-fit neutrino
parameters is now much larger, allowing any sin 2 2θ between about
10 −3 and 0.8. Notably the range of allowed large-angle solutions is
vastly increased.
In summary, the hypothesis of neutrino oscillations can beautifully
explain almost all experimental results to date. Only the curious anticorrelation
of the Homestake data with solar activity remains unaccounted
for. It is interpreted as a statistical fluctuation.