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Glossary · N

Neutrino oscillation

Periodic flavour change of a neutrino in flight, driven by the misalignment of mass and flavour eigenstates encoded by the PMNS matrix — requires non-zero mass.

Also: neutrino oscillations · flavour oscillation · flavor oscillation

Definition

Because flavor and mass eigenstates are misaligned, a ν of definite flavor produced at the source evolves as a coherent superposition of mass eigenstates with slightly different phase velocities. The interference produces an oscillating probability of being detected as a different flavor downstream, with characteristic baseline L/E.

Key equations

Two-flavor probability

See also

  • PMNS matrix The 3 × 3 unitary matrix that relates flavor and mass eigenstates of neutrinos.
  • MSW effect Coherent forward scattering on electrons modifies neutrino oscillation in matter, allowing resonant flavor conversion.
  • Mass ordering The ordering of the three neutrino mass eigenstates: normal (m_1 < m_2 < m_3) or inverted (m_3 < m_1 < m_2).
  • Flavor eigenstate A neutrino state defined by the charged lepton it produces in a charged-current interaction (ν_e, ν_μ, ν_τ).

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Formula

PMNS matrix

The 3 × 3 unitary matrix that mixes flavour with mass states.

Glossary

PMNS matrix

The 3 × 3 unitary matrix that relates flavor and mass eigenstates of neutrinos.