The Surprising History of Sterile Neutrinos

The 2015 Nobel Prize in Physics rewarded the discovery that neutrinos oscillate, and hence have mass. Now physicists are on the track of another discovery - a theorized fourth type of neutrino - that would certainly deserve a new Nobel Prize.

We already know that the Standard Model of particle physics must be expanded to account for neutrino mass. Finding a fourth type of neutrino beyond the three known types (electron, muon and tau) would require it to expand even further.

What makes this discovery tricky is that while the known types of neutrino interact with matter, the theorized additional neutrinos would not. However, effects of the existence of sterile neutrinos can be observed in laboratory experiments, since oscillations of the known types are affected by mixing with sterile neutrinos.

Indeed, some neutrino oscillation experiments have found exciting hints of the existence of sterile neutrinos, and this talk will review those findings. And new experiments will soon investigate whether these previously unseen types of neutrinos exist.

Discovering these particles would represent a major advance in our knowledge of fundamental physics.