A fundamental subatomic particle that is 207 times heavier than an electron. Muons have a mass of 0.106
GeV/, where c is the speed of light, and are negatively charged. The muon is one of six known types of
leptons. Muons are unstable; they decay to produce a virtualW-boson and a muon neutrino. The W-boson then decays to produce an electron and an
electron antineutrino. Muons are produced in particle physics experiments as well as by cosmic rays.
