From Albuquerque, N.M., at a meeting of the American Physical Society and American Astronomical Society
The case of the missing solar neutrinos is solved–again. New data from the deep subterranean Sudbury (Ontario) Neutrino Observatory (SNO) indicate that the sun produces all the neutrinos that solar theory says it should. Even so, that spells trouble for the prevailing theory, or standard model, of particle physics.
The wispy subatomic particles known as neutrinos come in three types, or flavors–electron neutrinos, muon neutrinos, and tau neutrinos–but the sun emits only electron neutrinos. In searches for that flavor since the 1960s, solar observers have always detected fewer than expected.