Tau (particle)

Uncommon card · No. 163865

The tau (τ, ), also called the tau lepton, tau particle or tauon, is an elementary particle similar to the electron, with negative electric charge and a spin of ⁠1/2⁠. Like the electron, the muon, and the three neutrinos, the tau is a lepton, and like all elementary particles with half-integer spin, the tau has a corresponding antiparticle of opposite charge but equal mass and spin. In the tau's case, this is the "antitau" (also called the positive tau). Tau particles are denoted by the symbol τ− and the antitaus by τ+. Tau leptons have a lifetime of 2.9×10−13 s and a mass of 1776.9 MeV/c2 (compared to 105.66 MeV/c2 for muons and 0.511 MeV/c2 for electrons). Because their interactions are very similar to those of the electron, a tau can be thought of as a much heavier version of the electron. Due to their greater mass, tau particles do not emit as much bremsstrahlung (braking radiation) as electrons; consequently they are potentially much more highly penetrating than electrons. Because...

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