We present a new measurement of the positive muon magnetic anomaly, aμ(gμ-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, p′, and of the anomalous precession frequency corrected for beam dynamics effects, ωa. From the ratio ωa/p′, together with precisely determined external parameters, we determine aμ=116 592 057(25)×10-11 (0.21 ppm). Combining this result with our previous result from the 2018 data, we obtain aμ(FNAL)=116 592 055(24)×10-11 (0.20 ppm). The new experimental world average is aμ(exp)=116 592 059(22)×10-11 (0.19 ppm), which represents a factor of 2 improvement in precision.

Measurement of the Positive Muon Anomalous Magnetic Moment to 0.20 ppm

Bedeschi F.;Hu Y.;Lee S.;Li D.;Lusiani A.
Membro del Collaboration Group
;
Quinn B.;Roberts B. L.;
2023

Abstract

We present a new measurement of the positive muon magnetic anomaly, aμ(gμ-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, p′, and of the anomalous precession frequency corrected for beam dynamics effects, ωa. From the ratio ωa/p′, together with precisely determined external parameters, we determine aμ=116 592 057(25)×10-11 (0.21 ppm). Combining this result with our previous result from the 2018 data, we obtain aμ(FNAL)=116 592 055(24)×10-11 (0.20 ppm). The new experimental world average is aμ(exp)=116 592 059(22)×10-11 (0.19 ppm), which represents a factor of 2 improvement in precision.
2023
Settore FIS/01 - Fisica Sperimentale
Charged particles; Magnetic field effects; Anomalous magnetic moments; Fermilab; Magnetic anomalies; Magnetic-field; Measurements of; Muon decays; Muon distributions; Positive muons; Precession frequency; Running conditions
   advanced Muon Campus in US and Europe contribution
   aMUSE
   European Commission
   Horizon 2020 Framework Programme
   101006726

   The strong interaction at the frontier of knowledge: fundamental research and applications
   STRONG-2020
   European Commission
   Horizon 2020 Framework Programme
   824093

   NEw WindowS on the universe and technological advancements from trilateral EU-US-Japan collaboration
   NEWS
   European Commission
   Horizon 2020 Framework Programme
   734303
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11384/139390
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