Holy (Neutrino) Trinity

Today the MiniBooNE collaboration released their first year results. For the press release, check here. For a full explanation, see that guest post at Cosmic Variance, or this one by Tommaso Dorigo. According to the press release,

The observations made by the LSND collaboration also suggested the presence of neutrino oscillation, but in a neutrino mass region vastly different from other experiments. Reconciling the LSND observations with the oscillation results of other neutrino experiments would have required the presence of a fourth, or "sterile" type of neutrino, with properties different from the three standard neutrinos.
[...]

The MiniBooNE collaboration ruled out the simple LSND oscillation interpretation by looking for signs of muon neutrinos oscillating into electron neutrinos in the region indicated by the LSND observations.

That is, to the best of our present knowledge, the necessary number of families (and mass eigenstates) in the Standard Model is three!

Update: Scientific American has a short article on that.