Muon

The muon ( /ˈmjuːɒn/; from the Greek letter mu (μ) used to represent it) is an elementary particle similar to the electron, with unitary negative electric charge (−1) and a spin of 1⁄2. Together with the electron, the tau, and the three neutrinos, it is classified as a lepton. As is the case with other leptons, the muon is not believed to have any sub-structure at all (i.e., is not thought to be composed of any simpler particles).

The muon is an unstable subatomic particle with a mean lifetime of 2.2 µs. This comparatively long decay lifetime (the second longest known) is due to being mediated by the weak interaction. The only longer lifetime for an unstable subatomic particle is that for the free neutron, a baryon particle composed of quarks, which also decays via the weak force. All muons decay to three particles (an electron plus two neutrinos of different types), but the daughter particles are believed to originate newly in the decay.

Like all elementary particles, the muon has a corresponding antiparticle of opposite charge (+1) but equal mass and spin: the antimuon (also called a positive muon). Muons are denoted by μ− and antimuons by μ+. Muons were previously called mu mesons, but are not classified as mesons by modern particle physicists (see History).

Muons have a mass of 105.7 MeV/c2, which is about 200 times the mass of an electron. Since the muon's interactions are very similar to those of the electron, a muon can be thought of as a much heavier version of the electron. Due to their greater mass, muons are not as sharply accelerated when they encounter electromagnetic fields, and do not emit as much bremsstrahlung (deceleration radiation). This allows muons of a given energy to penetrate far more deeply into matter than electrons, since the deceleration of electrons and muons is primarily due to energy loss by the bremsstrahlung mechanism. As an example, so-called "secondary muons", generated by cosmic rays hitting the atmosphere, can penetrate to the Earth's surface, and even into deep mines.

Because muons have a very large mass and energy compared with the decay energy of radioactivity, they are never produced by radioactive decay. They are, however, produced in copious amounts in high-energy interactions in normal matter, during certain particle accelerator experiments with hadrons, or naturally in cosmic ray interactions with matter. These interactions usually produce pi mesons initially, which most often decay to muons.

As with the case of the other charged leptons, the muon has an associated muon neutrino, which is not the same particle as the electron neutrino, and does not participate in the same nuclear reactions. Muon neutrinos are denoted by ν
μ.

Read more about Muon:  History, Muon Sources, Muon Decay, Muonic Atoms, Use in Measurement of The Proton Charge Radius, Anomalous Magnetic Dipole Moment

Other articles related to "muon, muons":

Muon - Anomalous Magnetic Dipole Moment
... experiment at Brookhaven National Laboratory (BNL) studied the precession of muon and anti-muon in a constant external magnetic field as they circulated in a confining storage ring ... The prediction for the value of the muon anomalous magnetic moment includes three parts αμSM = αμQED + αμEW + αμhad ... The difference between the g-factors of the muon and the electron is due to their difference in mass ...
Michel Parameters - Muon Decay
... See also Muon#Muon decay Let us consider the decay of the positive muon In the muon rest frame, energy and angular distributions of the positrons emitted in the ... For the decay of the negative muon, the sign of the term containing should be inverted ... For the decay of the positive muon, the expected decay distribution for the Standard Model values of Michel parameters is Integration of this expression over electron ...
Muon Spin Spectroscopy - How It Works - The Technique - Muon Implantation
... The muons are implanted into the sample of interest where they lose energy very quickly ... electron capture) in origin and do not interact with the muon spin, so that the muon is thermalized without any significant loss of polarization ... The positive muons usually adopt interstitial sites of the crystallographic lattice ...
Bilepton
... It can mediate exotic processes such as V+A muon decay and muonium-antimuonium conversion ... such as electron plus electron goes to muon plus muon which is forbidden in the Standard Model ... measurements made at the Paul Scherrer Institute (PSI) have searched for the exotic muon decay and placed a lower bound on the bilepton mass of about 1 TeV ...
ANTARES (telescope) - Design
... On rare occasions, a few muon neutrinos interact with the water in the Mediterranean Sea ... When this happens, they produce a high energy muon ... tubes detecting the Cherenkov radiation emitted as the muon passes through the water ...