The magnetic moment anomaly aμ = (gμ - 2)/2 of the positive muon has been measured at the Brookhaven Alternating Gradient Synchrotron with an uncertainty of 0.7 ppm. The new result, based on data taken in 2000, agrees well with previous measurements. Standard Model evaluations currently differ from the experimental result by 1.6 to 3.0 standard deviations.
Bibliographical noteFunding Information:
This work was supported by the U.S. Department of Energy, the U.S. National Science Foundation, the German Bundesminister ffir Bildung und Forschung, the Russian Ministry of Science, and the US-Japan Agreement in High Energy Physics. Mario Deile acknowledges support by the Alexander von Humboldt Foundation.