The anomalous magnetic moment of negative muon was analyzed at Brookenhaven Alternating gradient Synchrotron. The magnetic moment was measured to precision of 0.7 ppm which was based on muon spin precession in magnetic storage ring with electrostatic focusing. The number of decay electrons above an energy threshold was counted to determine difference frequency. The muons with low momenta decayed early as compared to muons of higher momenta and momentum distribution of stored beam also changed during 600μs measurement period.
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We thank T. Kirk, D. I. Lowenstein, P. Pile, and the staff of the BNL Alternating Gradient Synchrotron for the strong support they have given this experiment. This work was supported in part by the U.S. Department of Energy, the U.S. National Science Foundation, the U.S. National Computational Science Alliance, the German Bundesminister für Bildung und Forschung, the Russian Ministry of Science, and the U.S.-Japan Agreement in High Energy Physics.