There are six types of leptons, three of which have electrical charge
and three of which do not.
They are tiny particles without internal structure.
The best known lepton is the electron
(e-). The other two charged leptons
are the muon and the tau,
which are charged like electrons but have a lot more mass. The other leptons
are the three types of neutrinos.
They have no electrical charge, very little mass, and they are very hard to