4. Oscillations¶

Solar Neutrino Problem

The sun produces neutrinos inside it and the neutrinos are then propagating out through the plasma. On the earth we can detect them. A problem was that the detected neutrinos were only one third of the total neutrino flux predicted which causes some people to think that the sun had shut down. The solution, however, is the neutrino oscillation.

As far as we know, we have three flavours of neutrinos and their anti-particles which are orthogonal to each other,

\[\begin{split}\braket{\nu_{l'}}{\nu_l} &= \delta_{l'l} \\ \braket{\bar\nu_{l'}}{\bar\nu_l} &= \delta_{l'l} \\ \braket{\bar\nu_{l'}}{\nu_l} &= 0.\end{split}\]

The interesting thing about neutrinos is that it oscillates.