n.
Any member of a class of fermions that respond only to electromagnetic, weak, and gravitational forces and do not take part in strong interactions.
Leptons have a half-integral spin and obey the Pauli exclusion principle . They can either carry one unit of electric charge or be neutral. The charged leptons are the electrons, muons, and taus. Each has a negative charge and a distinct mass . Each charged lepton has an associated neutral partner, or neutrino , which has no electric charge and very little if any mass.