Discoveries in Muon Physics

The muon was first observed in cosmic rays by Paul Kunze in 1933 and positively identified by Seth H. Neddermeyer and Carl D. Anderson. The advent of proton cyclotrons with adequate energy to produce pions, p + N → π⁺ →μ⁺ + ν_{μ -bar}  enabled the development of beam of pions and muons.  The early muon beams contained a significant amount of pion contamination, and various schemes were developed to reduce/eliminate the pion contamination. Following the seminal paper by T.D. Lee and C.N. Yang, parity violation was observed in muon decays at the University of Chicago cyclotron, and at the Columbia Nevis cyclotron.  The technique used in the Nevis cyclotron parity violation experiment was also able to show that the g-factor of the muon was consistent with 2, as had been found previously for the electron.  We now understand that the muon is the second generation lepton in the Standard Model.  In this talk I will discuss the history of muon physics and its contribution to our understanding of the weak interaction, as well as pointing to the generation structure of the Standard Model.