Particle Physics an unstable, negatively charged lepton with a mass of 105.7 MeV, c. 207 times that of an electron, and a mean lifetime of 2.2×10 second: it decays into an electron, a neutrino, and an antineutrino
Origin of muonmu + (mes)on
The negatively charged lepton that belongs to the second generation of elementary fermions and has a mass 207 times that of an electron and a mean lifetime of 2.2 × 10−6 second. Also called mu lepton.
Origin of muonEarlier mu meson (from the use of the Greek letter mu, the equivalent of the Roman letter m of MESON, to distinguish it from other mesons subsequently discovered, the class of particles to which it was formerly thought to belong).
- An unstable elementary particle in the lepton family, having similar properties to the electron but with a mass 209 times greater.
Contraction of mu-meson (the particle has now been recategorised as a lepton).