muon

American  

[myoo-on] / ˈmyu ɒn /

noun

Physics.

1. a lepton similar in most respects to the electron except that it is unstable, it may be positively charged, and its mass is approximately 207 times greater; the positively charged muon is the antiparticle of the negatively charged muon. μ

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muon British  

/ ˈmjuːɒn, mjuːˈɒnɪk /

noun

1. a positive or negative elementary particle with a mass 207 times that of an electron and spin 1/ 2 . It was originally called the mu meson but is now classified as a lepton

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muon Scientific  

/ myo̅o̅′ŏn′ /

1. An elementary particle in the lepton family having a mass 209 times that of the electron, a negative electric charge, and a mean lifetime of 2.2 × 10 ^{- 6} seconds. The muon was originally called the mu-meson and was once thought to be a meson.

2. See Table at subatomic particle

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Other Word Forms

• muonic adjective

Etymology

Origin of muon

1950–55; by shortening of mu meson; mu, -on ¹

Example Sentences

Reaching this level requires advances throughout the entire experimental system, including a powerful surface muon beam, a newly developed silica aerogel target, and detectors capable of extremely precise measurements.

From Science Daily • Feb. 2, 2026

SNO+ is a successor to the earlier SNO experiment, which demonstrated that neutrinos switch between three forms known as electron, muon, and tau neutrinos as they travel from the Sun to Earth.

From Science Daily • Dec. 12, 2025

In the normal case, muon neutrinos are more likely to become electron neutrinos, while their antimatter partners are less likely to do so.

From Science Daily • Oct. 30, 2025

With a mass 207 times an electron’s, a muon radiates far less energy as it goes in circles, so a muon collider could reach much higher energy than a circular e+e- machine.

From Science Magazine • Mar. 27, 2024

The world's ultimate pragmatist just shrugs and says: "NhUng gi minh mong it khi nao no jcay ra. Nhung gi minh khong muon thi no lai cti den."

From "Counting by 7s" by Holly Goldberg Sloan