Aguillard, D. P.Albahri, T.Allspach, D.Anisenkov, A.Badgley, K.Baessler, S.Bailey, I.2024-05-192024-05-1920230031-90071079-7114https://doi.org10.1103/PhysRevLett.131.161802https://hdl.handle.net/20.500.12713/5867We present a new measurement of the positive muon magnetic anomaly, a, equivalent to (g,- 2)/2, from the Fermilab Muon g - 2 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, w similar to ip, and of the anomalous precession frequency corrected for beam dynamics effects, wa. From the ratio wa/w similar to ip, together with precisely determined external parameters, we determine a, = 116 592 057(25) x 10-11 (0.21 ppm). Combining this result with our previous result from the 2018 data, we obtain a,(FNAL) = 116592055(24) x 10-11 (0.20 ppm). The new experimental world average is a,(exp) = 116 592 059(22) x 10-11 (0.19 ppm), which represents a factor of 2 improvement in precision.eninfo:eu-repo/semantics/openAccess[No Keywords]Article1311637925710WOS:001105904700004N/A10.1103/PhysRevLett.131.161802