Measurement of the Positive Muon Anomalous Magnetic Moment to 127 ppb

UNSPECIFIED (2025) Measurement of the Positive Muon Anomalous Magnetic Moment to 127 ppb. Physical review letters, 135 (10): 101802. ISSN 1079-7114

Abstract

A new measurement of the magnetic anomaly a_{μ} of the positive muon is presented based on data taken from 2020 to 2023 by the Muon g-2 Experiment at Fermi National Accelerator Laboratory (FNAL). This dataset contains over 2.5 times the total statistics of our previous results. From the ratio of the precession frequencies for muons and protons in our storage ring magnetic field, together with precisely known ratios of fundamental constants, we determine a_{μ}=1 165 920 710(162)×10^{-12} (139 ppb) for the new datasets, and a_{μ}=1 165 920 705(148)×10^{-12} (127 ppb) when combined with our previous results. The new experimental world average, dominated by the measurements at FNAL, is a_{μ}(exp)=1 165 920 715(145)×10^{-12} (124 ppb). The measurements at FNAL have improved the precision on the world average by over a factor of 4.