An important recent discovery in physics came from measuring neutrinos—neutral, weakly interacting particles—produced by the sun. Nuclear reactions in the sun produce only electron neutrinos. According to the standard model, neutrinos come in three distinct “flavors” (electron, mu, and tau). Scientists originally thought neutrinos to be massless, but they recently discovered that neutrinos have mass.
Click here for original story, Theoretical and experimental physics team up in the search for particle flavor change
Source: Phys.org