) are like the electron except they are
more massive then it. "Lepton" originally meant "light" mass, but the
tau lepton is more then 3000 times more massive then the electron.
The other three leptons are very elusive particles called
neutrinos(
),
which have no electric charge and very little, if any mass.
There is one type of neutrino corresponding to each type of electrically
charged lepton. For each of the six leptons there is an antilepton
with equal mass and opposite charge.
