The Anomalous Magnetic Moment of the Muon

The anomalous part of the gyromagnetic ratio,\(a = \frac{1}{2}(g - 2)\) of the muon has been measured by determining the precession θ= aω0-Bt for 100 MeV/c muons as a function of storage timet in a known static magnetic field of the formB=B0(1+ay+by2+cy3+dy4). The result is aexp = (1162±5)·10-6 compared with the theoretical value ath=α/2π+0.76α2/π2=1165·10−6. This agreement shows that the muon obeys standard quantum electrodynamics down to distances ∼ 0.1 fermi. Details are given of the methods used to store muons for ∼ 103 turns in the field, and of measuring techniques and precautions necessary to achieve the final accuracy. Some of the methods of orbit analysis, magnet construction shimming and measurement, polarization analysis, and digital timing electronics may be of more general interest.