Physics Colloquium - Neutrino Moonshot: The Next Two Decades

The neutrino is perhaps the most enigmatic of fundamental particles. Its neutral charge and astonishingly low mass make its detection, and therefore its use in fundamental physics laboratories, exceedingly difficult. Despite this, it is in the neutrino sector where we have recently seen challenges to the long-standing Standard Model of Particle Physics. The neutrino is also an important player and messenger to the physics that takes place in astrophysical environments and the early Universe-it is one of the most hopeful windows to New Physics. In this talk, I will discuss a high-risk, high reward, multi-decade, world-wide research program that seeks to answer many of the open questions about the neutrino. What is the mass of the neutrino? Is there a 4th generation? What are the sizes of the electromagnetic form factors and the effective neutrino charge radius? What can it tell us about neutron skin depth and the equation of state of neutron stars? Does it play a role in the rapid process for the creation of heavy elements? Is lepton number conserved? What can it tell us about the weak charge? Are there any new force carriers? I will also touch on how these experiments can help search for the putative Dark Matter in our Universe. These are some of the questions that the LEGEND neutrinoless double beta decay experiment, and the COHERENT elastic neutrino-nucleus suite of experiments seek to answer over the next 20+ years.