Tau Lepton
The third-generation elementary charged lepton, with a mass approximately 3,477 times heavier than an electron.
Governing formula
m_τ ≈ 1776.8 MeV/c², τ_τ ≈ 2.9 × 10⁻¹³ s, Spin = ½
SI unit
MeV/c² (Mass Energy)
In depth
Discovered by Martin Perl in 1975. Due to its massive rest mass (~1.777 GeV/c²), the tau is the only lepton heavy enough to decay into hadronic final states (like pions) as well as lighter leptons.
Examples in the real world
Tau lepton pair production in high-energy electron-positron collisions at particle colliders.