Tau lepton

There are six different kinds of leptons (light particles) (Table 1.6), and they can be arranged in three pairs. The electron (e), the muon (p,), and the tau lepton (t) each carry a charge of —e and have associated with them the electron (ve), muon (VjJ, and tau neutrinos (vT). These neutrinos are electrically neutral and have small or zero rest mass. The actual mass of the neutrinos is a subject of current research (see Chapter 12). The electron neutrino is seen in nuclear phenomena such as (3 decay, whereas the other neutrinos are involved in higher energy processes. 

There are three known flavors of neutrinos the electron neutrino z/e, the muon neutrino and the tau neutrino ur. They are so named because they are produced or destroyed in concomitance with the electron, the muon, and the tau lepton, respectively. 

If the electron is seen as the ground state of a subsystem analogous to the Bohr atom, then the parent mu and tau leptons could be seen as its excited states , with a Compton radius decreasing as the rest mass increases. 

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