Abstract
We present a new measurement of the positive muon magnetic anomaly, , from the Fermilab Muon Experiment using data collected in 2019 and 2020. We have analyzed more than 4 times the number of positrons from muon decay than in our previous result from 2018 data. The systematic error is reduced by more than a factor of 2 due to better running conditions, a more stable beam, and improved knowledge of the magnetic field weighted by the muon distribution, , and of the anomalous precession frequency corrected for beam dynamics effects, . From the ratio , together with precisely determined external parameters, we determine (0.21 ppm). Combining this result with our previous result from the 2018 data, we obtain (0.20 ppm). The new experimental world average is (0.19 ppm), which represents a factor of 2 improvement in precision.
- Received 10 August 2023
- Accepted 5 September 2023
DOI:https://doi.org/10.1103/PhysRevLett.131.161802
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.
Published by the American Physical Society