Tau (particle physics)

A tau is an elementary particle in the Standard Model of particle physics. It carries a negative elementary charge −e, where

e = 1.60218 × 10-19 C.

The tau mass is 3.168 × 10-27 kg = 1,777 MeV/c2, which is 3,477 times the mass of the electron.

Taus are not stable particles, and decay with a mean lifetime of 2.9 × 10-13 s.