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n. An elementary particle in the lepton family (not a meson), having a mass 209 times that of the electron, a negative electric charge, and a mean lifetime of 2.2 × 10-6 seconds. Also called mu meson. See Table at subatomic particle.

n. An unstable elementary particle in the lepton family, having similar properties to the electron but with a mass 209 times greater.

n. an elementary particle with a negative charge and a half-life of 2 microsecond; decays to electron and neutrino and antineutrino

"It was then realized that the particle found by Anderson could not be the meson of strong interactions, since it interacted far too little with matter, and it was then shown that this particle, now called the muon, is a heavy cousin of the electron."

lepton   

energy-dispersive    sixty-mile    posigravity    photoelectron    infrared    matter-antimatter    upsilon    holesare    inwnitesimal    seven-mile