by the DONUT experiment [101]
the standard model is complete except for the Higgs boson. Neutrinos
played a significant role in establishing the standard model, while
the observation of neutrino mass has also provided the first evidence
for new physics. The evidence for neutrino mass and mixing is now
convincing. New generations of experiments should establish the
neutrino mass and mixings, hopefully determine their nature (Dirac or
Majorana) and number, and perhaps establish leptonic CP violation.
Not only will this be a superb constraint on what underlies the standard
model, but neutrinos are also a critical probe of astrophysical
processes, from stars to gamma ray bursts and the universe as a whole.