ISSN - 00319007, EISSN - 10797114, Physical Review Letters, 1999, vol. 82, p. 1632-1635
New Measurement of the Anomalous Magnetic Moment of the Positive Muon
The muon anomalous magnetic moment has been measured in a new experiment at Brookhaven. Polarized muons were stored in a superferric ring, and the angular frequency difference, ωa, between the spin precession and orbital frequencies was determined by measuring the time distribution of high-energy decay positrons. The ratio R of ωa to the Larmor precession frequency of free protons, ωp, in the storage-ring magnetic field was measured. We find R = 3.707 220(48) × 10-3. With μμ/μp = 3.183 345 47(47) this gives aμ+ = 1 165 925(15) × 10-9 (±13ppm), in good agreement with the previous CERN measurements for μ+ and μ- and of approximately the same precision.