Improved Measurement of the Positive Muon Anomalous Magnetic Moment

TL;DR

This paper reports a more precise measurement of the positive muon's anomalous magnetic moment, confirming previous results and aligning with the Standard Model predictions, using advanced experimental techniques at Brookhaven.

Contribution

It introduces a new measurement method for the muon g-2 with improved accuracy, utilizing direct polarized muon injection and refined frequency measurements.

Findings

Measured a_{mu^+} = 11,659,191(59) x 10^{-10}

Results agree with previous experiments and Standard Model

Achieved a precision of 5 ppm

Abstract

A new measurement of the positive muon's anomalous magnetic moment has been made at the Brookhaven Alternating Gradient Synchrotron using the direct injection of polarized muons into the superferric storage ring. The angular frequency difference omega_{a} between the angular spin precession frequency omega_{s} and the angular orbital frequency omega_{c} is measured as well as the free proton NMR frequency omega_{p}. These determine R = omega_{a} / omega_{p} = 3.707~201(19) times 10^{-3}. With mu_{mu} / mu_{p} = 3.183~345~39(10) this gives a_{mu^+} = 11~659~191(59) times 10^{-10} (pm 5 ppm), in good agreement with the previous CERN and BNL measurements for mu^+ and mu^-, and with the standard model prediction.