https://waveform-particle-state.blogspot.com/ Near the end of the 1900s, scientists found the tau neutrino. It is the last of the fundamental building blocks of matter. It took six million tries to find the four events that proved the tau neutrino exists. The magic number of building blocks of matter appears to be six. That is, there are six quarks, and six leptons. The tau neutrino, which is a lepton, was the last of the dozen. The tau lepton, which is what the tau neutrino becomes, after hitting an atomic nucleus, such as iron, quickly disappears. The only evidence the tau lepton leaves is a one millimeter track.