ABSTRACT
Neutrinos are the only known electrically neutral fermions, and exist in three separate flavors. Neutrinos are much lighter than all other known fermions, and in fact all attempts to measure their mass have only yielded upper limits. However if neutrinos have non-vanishing masses, they are able to change their flavor during propagation. This phenomenon is known as neutrino (flavor) oscillations In general, the neutrino states with well defined flavor: (νe, νμ , ντ ) and the states with well defined mass:(ν1, ν2, ν3) do not coincide. The two triplets are related by a Unitary matrix.
