A fourth neutrino could help explain dark matter

Physicists working with a Fermilab neutrino experiment may have found a new elementary particle whose behavior breaks the known laws of physics. If correct, their results poke holes in the accepted Standard Model of particles and forces, and raise some interesting questions for the Large Hadron Collider and Tevatron experiments. The new particle could even explain the existence of dark matter.

Working with Fermilab’s MiniBooNE experiment — the first part of the larger planned Booster Neutrino Experiment — physicists found evidence for a fourth flavor of neutrino, according to a new paper published in Physical Review Letters. This means there could be another particle we didn’t know about, and that it behaves in a way physicists didn’t expect.

Neutrinos have been mystifying physicists since they were first theorized decades ago. They are one of the building blocks of matter, and to the best of our knowledge, they come in three varieties, called flavors: electron neutrinos, muon neutrinos and tau neutrinos. Oscillation is what happens when neutrinos turn from one flavor to another; an electron neutrino might turn into a muon neutrino, and then turn back again. How often they do this tells physicists about the infinitesimally small differences in their masses. Neutrino mass is important because it may lead us to physics beyond the Standard Model. And that is exactly what seems to have happened.