Neutrino Masses and Oscillations

Abstract.

LEP era has established the validity of the Standard Model (SM) at better than the 1% level [1]. This is a gauge theory based on the group SU(3) x SU(2) x U(1), which is spontaneously broken to the subgroup describing the strong and electromagnetic interactions SU(3) x U(1) _em . In this process the boson mediating the weak interactions adquire a mass. The recent discovery of the last missing particles $\nu_\tau$ and t, which were predicted a long time ago, has confirmed the family structure shown in Table 1.