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Neutrino oscillations
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Neutrinos change flavour, indicating mass.
Neutrinos change flavour as they travel, which requires mass differences; discovered at Super-Kamiokande and SNO (Nobel 2015). The Standard Model originally had massless neutrinos.
Solar electron neutrinos arrive as other flavours.
Absolute masses are below 0.1 eV.
In more detail
Neutrino oscillation means neutrinos change flavour as they travel, which implies that they have mass. The effect was discovered through observations of solar and atmospheric neutrinos.
Real-world uses
- Neutrino oscillation experiments have revealed neutrino masses.
- Underground detectors study oscillations with reactors and accelerators.
- Neutrino experiments detected changing neutrino flavours, which showed that neutrinos have a small but nonzero mass.
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Frequently asked questions
Why does oscillation prove mass?
Only particles with different masses can have flavour states that change over time.
Who won the Nobel Prize for it?
Takaaki Kajita and Arthur McDonald, in 2015.
What is neutrino oscillation?
The change of a neutrino from one flavour into another as it travels, which can only happen if neutrinos have mass.
Related topics in Particle Physics & Cosmology
Particle accelerators · Large Hadron Collider · Particle detectors · CP violation · Matter–antimatter asymmetry · Grand unified theories