Solving equations in neutrino physics, a trio of theorists doing research at Fermilab discovered a mathematical identity that had eluded mathematicians for centuries. Working with Field Medal winner Terence Tao, they now have derived formal proofs of the new identity.
Keep an eye out for the neutrino question of the week.
If neutrinos were massless, they would be always traveling at the speed light. This means that, as Einstein informed us, their clocks would not tick, and thus neutrinos could not change from one type to another. This stands in contradiction to neutrino oscillations observed in many neutrino experiments, such as the transformation of a muon neutrino into an electron neutrino recently reported by the Fermilab NOνA experiment.