A Fourth Neutrino?

Neutrinos have come a long way from being considered undetectable to being the focus point of billion-dollar experiments. And while we have learned a lot about their properties over the past decades, the standard theory of neutrinos has a few noteworthy dents in the form of seemingly anomalous experimental results. We review these anomalies and use them to illustrate some of the challenges in making reliable theoretical predictions for neutrino experiments. We also speculate about the possibility that the anomalies are indeed harbingers of “new physics” in the form of a yet-unknown extra neutrino species.

Host: Wei Xue