GC: n

CT: A muon is a type of subatomic particle. The name is pronounced “myoo-on,” and comes from the Greek letter µ, which we spell “mu” and pronounce “myoo.” A muon is a type of particle very much like an electron. In fact, it is exactly the same as an electron – except heavier. The mass of a muon is 207 times the mass of an electron. You can remember or look up (or take our word for it) that the mass of a proton, by contrast, is about 1,800 times the mass of an electron.
So a muon has all the properties of an electron, but is more similar in mass to the big clunkiness (in relative terms) of a proton or other nuclear particle. .

S: Vanderbilt – (last access: 8 December 2018).

N: 1. 1950s: contraction of mu-meson; the particle, however, is no longer regarded as a meson.
2. An elementary particle with 207 times the mass of an electron. It may have a single positive or negative charge.
3. It has two forms, the negatively charged muon and its positively charged antiparticle.
4. A muon is correctly assigned as a member of the lepton group of subatomic particles—i.e., it never reacts with nuclei or other particles through the strong interaction.
5. A muon is relatively unstable, with a lifetime of only 2.2 microseconds before it decays by the weak force into an electron and two kinds of neutrinos. Because muons are charged, before decaying they lose energy by displacing electrons from atoms (ionization). At high-particle velocities close to the speed of light, ionization dissipates energy in relatively small amounts, so muons in cosmic radiation are extremely penetrating and can travel thousands of metres below the Earth’s surface.
6. Muons, leptons produced in hadronic showers, can penetrate km-scale structures.
7. Muons produced in extended air showers have been used to map the interior of large structures on Earth.

S: 1. OD – (last access: 5 December 2018). 2. TERMIUM PLUS – (last access: 5 December 2018). 3 to 5. EncBrit – (last access: 5 December 2018). 6 & 7. NASA – (last access: 5 December 2018).

SYN: mu-meson

S: TERMIUM PLUS – (last access: 8 December 2018)

CR: atom, electron , ion , lepton , linear accelerator, neutrino , nuclear energy, particle, proton , quark , synchrotron, X-rays.