to include the electron, the muon, and their associated neutrinos 包括电子、介子以及与他们相关的中子
When two such gamma-ray beams collide, the interactions are even cleaner than electron-positron or muon-antimuon collisions. 当这样的两束伽玛射线碰撞时,其交互作用比「电子╱正子」或「缈子╱反缈子」的碰撞更乾净。
The muon (/ˈmjuːɒn/; from the Greek letter mu (μ) used to represent it) is an elementary particle similar to the electron, with electric charge of −1e and a spin of ⁄2, but with a much greater mass. It is classified as a lepton. As is the case with other leptons, the muon is not believed to have any sub-structure—that is, it is not thought to be composed of any simpler particles.