Proof of three neutrino types. This graph from the ALEPH experiment at CERN,the particle physics laboratory near Geneva,shows three possible 'resonance' peaks of the Z particle,based on the existence of two,three or four types of neutrino. Only the middle curve,for three neutrino types,fits the data (black dots) from ALEPH,which observed millions of Z particles created at CERN's LEP collider. Proof of 3 neutrino types (electron- neutrino,muon- neutrino,tau-neutrino) confirms the 'standard model' of fundamental particles in which a family of six quarks is matched by a family of six leptons (which include the three types of neutrino) |