mu-meson n 1: an elementary particle with a negative charge and a half- life of 2 microsecond; decays to electron and neutrino and antineutrino [syn: {muon}, {negative muon}, {mu-meson}]
mu-meson \mu-meson\, mu meson \mu meson\n. (Physics) an elementary particle with a negative charge and a half-life of 2 microseconds; the muon. It is a lepton, not a true meson, and decays to an electron and neutrino and antineutrino. Syn: muon, negative muon. [WordNet 1.5]