Neutrino ❍｜appendage｜___｜20260913160020-01-•

A	B
The first use of a hydrogen bubble chamber to detect neutrinos, on 13 November 1970, at Argonne National Laboratory. Here a neutrino hits a proton in a hydrogen atom; the collision occurs at the point where three tracks emanate on the right of the photograph.	…
Composition	Elementary particle
Statistics	Fermionic
Family	Leptons, antileptons
Generation	First (ν ${}_e$), second (ν ${}_{\mu }$), and third (ν ${}_{\tau }$)
Interactions	Weak interaction and gravitation
Symbol	ν ${}_e$ , ν ${}_{\mu }$ , ν ${}_{\tau }$ , ν ${}_e$ , ν ${}_{\mu }$ , ν ${}_{\tau }$
Particle	spin: ⁠±+1/2⁠ħ, chirality: Left, weak isospin: +⁠1/2⁠, lepton nr.: +1, “flavor” in { e, μ, τ }
Antiparticle	spin: ⁠±+1/2⁠ħ, chirality: Right, weak isospin: −⁠1/2⁠, lepton nr.: −1, “flavor” in { e, μ, τ }
Theorized	• ν ${}_e$ , electron neutrino : Wolfgang Pauli (1930) • ν ${}_{\mu }$ , muon neutrino : late 1940s • ν ${}_{\tau }$ , tau neutrino : mid-1970s
Discovered	• ν ${}_e$ : Clyde Cowan , Frederick Reines (1956) • ν ${}_{\mu }$ : Leon Lederman , Melvin Schwartz and Jack Steinberger (1962) • ν ${}_{\tau }$ : DONUT collaboration (2000)
Types	3 types: electron neutrino (ν ${}_e$), muon neutrino (ν ${}_{\mu }$), and tau neutrino (ν ${}_{\tau }$)
Mass	< 0.120 eV/c${}^2$ (< 2.14×10${}^{-37}$ kg), cosmological limit, sum of 3 “flavors”1
Electric charge	0 e
Spin	⁠1/2⁠ħ
Weak isospin	LH: +⁠1/2⁠, RH: 0
Weak hypercharge	LH: −1, RH: 0
B − L	−1
X	−3

Neutrino

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Footnotes

1. Olive, K.A.; et al. (Particle Data Group) (2024). Navas, S.; et al. (eds.). “Sum of neutrino masses” (PDF). Physical Review D. 110: 030001 – via Lawrence Berkeley Laboratory (lbl.gov). ↩