Properties of Neutrino Oscillations

Once we confirmed that neutrinos indeed oscillate between different flavors,  new questions became open:

What are the neutrino masses?

How far neutrinos travel before they change their flavor?

What fraction of neutrinos change into different flavor?

Besides neutrino masses, these questions called for new physical quantities needed to describe detailed properties of neutrino oscillations, namely neutrino mixing angles and neutrino squared mass differences:

Neutrino Mixing: measured mass differences are
shown on the y-axis. Note that the absolute masses
are not known, only the difference in mass of the
three types of neutrinos.

  • Neutrino mixing angles describe the amount of mixing among different flavors.
  • Squared neutrino mass differences govern the pattern of mixing (the length it takes to neutrino to oscillate).
  • The standard model was adjusted to account for neutrinos carrying mass and their oscillation properties. 
  • Two of the three mixing angles have been precisely determined: θ1-2, which describes electron neutrino to muon neutrino oscillation, and θ2-3, which accounts for muon neutrino to tau neutrino oscillations.
  • θ1-3, which models electron neutrino to muon and tau neutrino oscillations, remains to be measured to an accurate degree.
  • Squared mass differences between three neutrino mass states have been measured as well