Tau neutrino

The tau neutrino or tauon neutrino is a subatomic elementary particle which has the symbol ν
τ and no net electric charge. Together with the tau, it forms the third generation of leptons, hence its name tau neutrino. Its existence was immediately implied after the tau particle was detected in a series of experiments between 1974 and 1977 by Martin Lewis Perl with his colleagues at the SLAC–LBL group. The discovery of the tau neutrino was announced in July 2000 by the DONUT collaboration.

Discovery

The tau neutrino is last of the leptons, and is the second most recent particle of the Standard Model to be discovered. The DONUT experiment (which stands for Direct Observation of the Nu Tau) from Fermilab was built during the 1990s to specifically detect the tau neutrino. These efforts came to fruition in July 2000, when the DONUT collaboration reported its detection.

See also

References

Neutrino

A neutrino (/nuːˈtriːnoʊ/ or /njuːˈtriːnoʊ/) (denoted by the Greek letter ν) is a lepton, an elementary particle with half-integer spin, that interacts only via the weak subatomic force and gravity. The mass of the neutrino is tiny compared to other subatomic particles. Neutrinos are the only identified candidate for dark matter, specifically hot dark matter.

Neutrinos come in three flavors: electron neutrinos (ν
e), muon neutrinos (ν
μ), and tau neutrinos (ν
τ). Each flavor is also associated with an antiparticle, called an "antineutrino", which also has no electric charge and half-integer spin. Neutrinos are produced in a way that conserves lepton number; i.e., for every electron neutrino produced, a positron (anti-electron) is produced, and for every electron antineutrino produced, an electron is produced as well.

Neutrinos, named as such because they are electrically neutral, are leptons, and so are not affected by the strong force either. The weak force is a very short-range interaction, and gravity is extremely weak on the subatomic scale. Thus, neutrinos typically pass through normal matter unimpeded and undetected.