all about neutrinos...
Davis' experiment....an olympic sized swimming pool vat of cleaning fluid (ie, 37Cl) should capture the energetic neutrino generated in the ppIII reaction...
Surprising results... only 1/3 of expected neutrinos seen
Other experiments seem to show neutrino shortage
Possible solution? Neutrinos got mass!
As the neutrinos pass through the sun they can change "flavor" and so become undetectable in Davis' 37Cl experiment. Other detectors (Kamiokande,...) which are sensitive to other flavors seem to bear this out.
Recent results for cosmic ray induced neutrinos indicate passage through the Earth causes the flavor change. ....Still under investigation....