Measurement of the Negative Muon Anomalous Magnetic Moment to 0.7 ppm

The anomalous magnetic moment of the negative muon has been measured to a precision of 0.7 parts per million (ppm) at the Brookhaven Alternating Gradient Synchrotron. This result is based on data collected in 2001, and is over an order of magnitude more precise than the previous measurement of the negative muon. The result a_mu= 11 659 214(8)(3) \times 10^{-10} (0.7 ppm), where the first uncertainty is statistical and the second is sytematic, is consistend with previous measurements of the anomaly for the positive and negative muon. The average for the muon anomaly a_{mu}(exp) = 11 659 208(6) \times 10^{-10} (0.5ppm).Comment: 4 pages, 4 figures, submitted to Physical Review Letters, revised to reflect referee comments. Text further revised to reflect additional referee comments and a corrected Fig. 3 replaces the older versio

Radial magnetic field measurements with a Hall probe device in the muon (g-2) storage ring magnet at BNL

A Hall probe device has been built to measure the radial component of the magnetic field in the muon (g-2) storage ring at Brookhaven National Laboratory. The ultraprecise (g-2) magnet provides a dominantly vertical magnetic field of about 1.45 T. In order to limit the vertical shift of the muon orbit, the average radial field component should be no more than 5 x 10(-5) of, the vertical field. Our measurements with the Hall probe device achieved an accuracy of 1 x 10(-5). which is one of the most precise measurements with Hall probes. This provides adequate accuracy for shimming and control of the radial field. (C) 2001 Elsevier Science B.V. All rights reserved

A sensitive search for a muon electric dipole moment

We are proposing a new method to carry out a dedicated search for a permanent electric dipole moment (EDM) of the muon with a sensitivity at a level of 10(-24) e . cm in both statistics and systematics. This will make the sensitivity of the EDM experiment to non-standard physics better than the sensitivity of the present muon g-2 experiment, assuming the CP violating phase of the probed physics is of order one. The experimental design exploits the strong motional electric field sensed by relativistic particles in a magnetic storage ring.(1,2) As a key feature, a novel technique has been invented in which the g-2 precession is compensated with a radial electric field

Test results of the g-2 superconducting solenoid magnet system

The g-2 experiment dipole consists of a single 48 turn, 15.1 meter diameter outer solenoid and a pair of 24 turn inner solenoids, 13.4 meters in diameter. The inner solenoids are hooked in series and are run at a polarity that is opposite that of the outer solenoid, thus creating a dipole field in the space between the inner and outer solenoids, The dipole flux is returned by a C shaped continuous iron. The superconducting solenoid coils are closely coupled to the solenoid mandrels and as such are subject to quench back. This report presents the results of various tests on the g-2 magnet system operating within its iron return yoke. These tests include quench back time constant measurements for the inner and outer solenoids and measurements of the response of the two-phase forced cooled helium cryogenic system to magnet quenches. The overall effectivness of the g-2 magnet quench protection system was measured

Recent results from the BNL g-2 experiment

The status of the muon g - 2 experiment at the AGS facility of Brookhaven National Laboratory is discussed. Data obtained in 1999 with positive muons has been analyzed and published. The final data set contained 0.95 x 10(9) events and had an accuracy of 1.3ppm. Approximately four times more data with positive muons and three times more data with negative muons were obtained in 2000 and 2001, respectively. These data were obtained with a more uniform magnetic field and with different storage ring tunes. An accuracy of the order of 0.5ppm is anticipated