Run 2/3 measurement of the muon anomalous magnetic moment by the Muon g-2 experiment at Fermilab

TL;DR

The Fermilab Muon g-2 experiment's recent measurements using Run 2 and 3 data have significantly improved the precision of the muon magnetic moment anomaly, providing critical insights into potential physics beyond the Standard Model.

Contribution

This paper presents the latest measurement of muon g-2 with four times more data, achieving unprecedented precision and advancing the understanding of muon magnetic properties.

Findings

Achieved an uncertainty of 0.20 ppm in muon g-2 measurement.

Confirmed previous results with improved sensitivity.

Discussed implications for Standard Model predictions.

Abstract

The Muon g-2 experiment at Fermilab seeks to measure the muon magnetic moment anomaly, $a_\mu =(g-2)/2$, with a final target precision of 0.14 parts-per-million (ppm). The experiment's initial result, published in 2021 using Run 1 data from 2018, confirmed the previous measurement at Brookhaven National Laboratory with a comparable sensitivity of 0.46 ppm. In 2023, a new result based on Run 2 and Run 3 data, collected in 2019 and 2020, was released. These datasets contain four times the data from Run 1, significantly enhancing sensitivity and achieving an unprecedented uncertainty of 0.20 ppm. This advancement resulted in a two-fold improvement in both statistical and systematic uncertainties. Here, we will discuss the muon $g-2$ measurement, the increased precision relative to the Run 1 result, and provide an outlook on future measurements which will incorporate datasets from 2021 to 2023. Additionally, we will explore the implications of comparing the new measurements with the latest Standard Model predictions for muon g-2.