An improved limit on the electric dipole moment of the muon

A search for a muon electric dipole moment (EDM) has been performed at the Brookhaven National Laboratory muon storage ring using data from the 2000 run of the muon g − 2 experiment. An EDM in an elementary particle would violate parity and time reversal symmetry.; Polarized muons were injected into the 7m radius storage ring at 3.1GeV. The difference between their precession and cyclotron frequencies (ω _a = ω_p − ω _c) was measured to determine their anomalous magnetic moment. A muon EDM would cause a tilt in the precession plane, resulting in an oscillation in the vertical position of positron hits on the detectors at ω _a.; An oscillation amplitude of -1.3±5.9stat±10.4sys mm was measured, giving an EDM measurement of -0.1±1.4× 10^-19e-cm Given that this is consistent with zero, a new muon EDM limit of 2.8×10^-19e-cm 95%CL has been set. Combining this with the previous measurement of the muon EDM from the CERN g − 2 experiment [1] produces a limit of 2.7×10^-19e-cm 95%CL. ...