  Neutrinos are the most elusive particles in our universe. They have masses at
least one million times smaller than the electron mass, carry no electric
charge, and very weakly interact with other particles, meaning they are rarely
captured in terrestrial detectors. Tremendous efforts in the past two decades
have revealed that neutrinos can transform from one type to another as a
consequence of neutrino oscillations---a quantum mechanical effect over
macroscopic distances---yet the origin of neutrino masses remains puzzling. The
physical evolution of neutrino parameters with respect to energy scale may help
elucidate the mechanism for their mass generation.
