Extra neutrino flavor could be bitter end to Standard Model

Neutrinos have always caused the physics community a bit of grief. It took decades to go from the first hints of their existence to actually detecting their presence. Then, when studying solar neutrinos, scientists were stumped by an absence—far fewer showed up in the detectors than the Sun should be producing. This was eventually explained by what are called flavor oscillations, which cause neutrinos to shift among the three known types: electron, muon, and tau. Now, researchers are facing yet another enigma: antineutrinos undergo flavor oscillations at a different rate than their regular counterparts.