A search for an electric dipole moment of the positive muon

A search for an electric dipole moment of the positive muon has been performed at Brookhaven National Laboratory. This analysis was performed on drift tube chamber positron tracking data taken during the 1999 and 2000 runs of the muon g-2 experiment (E821). In the experiment, polarized muons are injected into a magnetic storage ring and the relative precession of their momentum and spin (oa = oc, - os) is measured as an oscillation in the rate of particles detected over an energy threshold. The presence of an EDM would result in a tilt in the vector about which the muon precesses in a direction normal to both the field and the momentum of the muon. The tilt of the precession plane can be measured as an oscillation in the average vertical decay angle of the positrons at the measured precession frequency. A new upper limit is set on the magnitude of an electric dipole moment of the positive muon at 2.6x10-19(e·cm). Combining this measurement with other direct measurements performed in the g-2 experiment yields a new world average limit of 1.9x10 -19(e·cm).