tauflavor

Tau flavor refers to the properties and interactions associated with the tau lepton, the third generation of leptons in the Standard Model. Leptons occur in three flavors: electron, muon, and tau. The tau flavor is carried by the charged tau lepton (τ) and its corresponding neutrino (ντ). In the electroweak theory, τ and ντ form a weak isospin doublet with the other lepton families.

The tau lepton has a mass of about 1776.86 MeV/c^2, carries electric charge −1, and has spin 1/2. It is the heaviest lepton and has a mean lifetime of about 2.9 × 10^−13 seconds. Because of its large mass, tau decays proceed to final states that include hadrons as well as purely leptonic channels. Roughly two-thirds of decays are hadronic; the rest split between electron and muon channels, all including a tau neutrino in the final state.

The associated neutrino, ντ, completes the tau flavor. Neutrino oscillations show flavor mixing in propagation, while charged-current interactions respect lepton flavor in the Standard Model.

In experiments, tau physics tests lepton flavor universality, constrains the weak couplings, and probes physics beyond the Standard Model, such as extended Higgs sectors or leptoquarks. Tau decays provide complementary information to electron and muon studies in precision tests and new-physics searches.