Understanding the Physics Behind Neutrino Masses

Nonzero neutrino masses are the most palpable evidence for physics beyond the Standard Model. Neutrino oscillations reveal, beyond reasonable doubt, that neutrino masses are not zero. While we can explain (almost all) neutrino data very successfully, the dynamical mechanism behind nonzero neutrino masses remains unknown. There are many compelling new physics scenarios capable of generating neutrino masses in a way that is consistent with the world's neutrino data, and it behooves us to figure out which one, if any, is realized by nature. I will pose the question, discuss a few possibility, and highlight some of the future experimental efforts that may help us piece the neutrino puzzle.