Muon

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Muon

The muon is an elementary particle similar to the electron, with an electric charge of −1 e and a spin of 1/2, but with a much greater mass. It is classified as a lepton. The muon is an unstable subatomic particle with a mean lifetime of 2.2 microseconds. Among all known particles, only the neutron and certain nuclei have a longer lifetime.

Discovery

The muon was discovered in 1936 by Carl D. Anderson and Seth Neddermeyer while they were studying cosmic rays. They initially mistook it for a meson, leading to some confusion in the particle physics community.

Properties

Muons are similar to electrons in that they are both leptons and have a charge of -1. However, the muon is approximately 207 times more massive than the electron. This greater mass means that muons do not emit as much bremsstrahlung radiation as electrons do when they are accelerated, which allows them to penetrate much deeper into matter.

Mass and Charge

• Mass: 105.66 MeV/c²
• Charge: -1 e

Lifetime

Muons are unstable and decay into an electron, a neutrino, and an antineutrino. The mean lifetime of a muon is about 2.2 microseconds.

Interactions

Muons interact with other particles primarily through the weak interaction and electromagnetic interaction. They do not participate in the strong interaction, which is why they are classified as leptons.

Applications

Muons have several applications in various fields of science and technology:

• In particle physics, muons are used in experiments to probe the structure of matter.
• In cosmic ray studies, muons are used to understand high-energy processes in the universe.
• In muon tomography, muons are used to image the interior of large objects, such as volcanoes and pyramids.

See also

• Electron
• Tau (particle)
• Lepton
• Cosmic ray
• Particle physics