Tau neutrino

Tau neutrino

Composition	Elementary particle
Statistics	Fermionic
Generation	Third
Interactions	Weak, Gravity
Symbol	ν τ
Antiparticle	Tau antineutrino (ν τ)
Theorized	Mid 1970s
Discovered	DONUT collaboration (2000)
Mass	Small but non-zero. See neutrino mass.
Electric charge	0 e
Color charge	No
Spin	1⁄2
Weak isospin	LH: ?, RH: ?
Weak hypercharge	LH: ?, RH: ?

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.^[1] The discovery of the tau neutrino was announced in July 2000 by the DONUT collaboration.^[2][3]

Discovery

Main article: DONUT

The tau neutrino is last of the leptons, and the 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.^[2][3]

With this discovery, only one Standard Model particle remains undiscovered – the Higgs boson.

See also

• Electron neutrino
• Muon neutrino
• PMNS matrix

References

1. ^ M. L. Perl et al. (1975). "Evidence for Anomalous Lepton Production in e+
   e−
   Annihilation". Physical Review Letters 35 (22): 1489. Bibcode 1975PhRvL..35.1489P. doi:10.1103/PhysRevLett.35.1489. 
2. ^ ^{a b} "Physicists Find First Direct Evidence for Tau Neutrino at Fermilab" (Press release). Fermilab. 20 July 2000. http://www.fnal.gov/pub/presspass/press_releases/donut.html. 
3. ^ ^{a b} K. Kodama et al. (DONUT Collaboration (2001). "Observation of tau neutrino interactions". Physics Letters B 504: 218. arXiv:hep-ex/0012035. Bibcode 2001PhLB..504..218D. doi:10.1016/S0370-2693(01)00307-0.