Status of the BNL muon (g-2) experiment

The muon (g-2) experiment at Brookhaven completed a first run in June and July 1997. The main components of the experiment, which include the superconducting inflector, the superferric storage ring, the electrostatic quadrupoles and the lead-scintillating fiber electron calorimeters, have been commissioned satisfactorily. Our first measurement of the ratio R of the spin precession frequency of the positive muon relative to that of a free proton, R=(3.707219/spl plusmn/0.000048)/spl times/10/sup -3/, is in good agreement with the previous CERN measurements for /spl mu//sup +/ and /spl mu//sup -/, and has approximately the same uncertainty as each of these measurements. In spring 1998 a muon kicker was installed and successfully tested in the storage ring magnet and a significant improvement in the knowledge of the muon g-factor is expected from upcoming runs in August 1998 and January 1999.