Solution of the Problem—Neutrino Oscillations

The solution to the solar neutrino problem is that something is wrong with our ideas of the fundamental structure of matter, the so-called standard model. This difficulty takes the form of neutrino oscillations as the solution to the solar neutrino 

Total Rata Standard Modal v Expanmant Bahcall Pmsonneault 2000 

The direct observational evidence for the occurrence of neutrino oscillations came from observations with the Cerenkov detectors. The SNO detector found one-third the expected number of electron neutrinos coming from the sun in agreement with previous work with the radiochemical detectors. The Super Kamiokande detector, which is primarily sensitive to electron neutrinos, but has some sensitivity to other neutrino types found about one-half the neutrino flux predicted by the standard 

---