Toward the Frontiers of Particle Physics With the Muon $g\textrm{-}2$ Experiment

TL;DR

The Muon g-2 experiment at Fermilab aims to measure the muon anomalous magnetic moment with unprecedented precision to investigate potential signs of new physics beyond the Standard Model.

Contribution

This paper describes the experimental setup, measurement techniques, and systematic controls of the Fermilab Muon g-2 experiment, advancing the precision of muon anomaly measurements.

Findings

Experiment has commenced Run-3 data collection.

Preparation for Run-1 physics results release in 2020.

Enhanced magnetic field uniformity and systematic controls implemented.

Abstract

The Muon $g\textrm{-}2$ Experiment (E989) at Fermilab has a goal of measuring the muon anomaly ($a_\mu$) with unprecedented precision using positive muons. This measurement is motivated by the difference between the previous Brookhaven $a_\mu$ measurement and Standard Model prediction exceeding three standard deviations, which hints at the possibility of physics beyond the Standard Model. Muons are circulated in a storage ring, and the measurement requires a precise determination of the muon anomalous precession frequency (spin precession relative to momentum) from the resulting decay positron time and energy measurements collected with calorimeters. The average magnetic field seen by the muons needs to be known with high precision, and so the storage ring magnetic field is shimmed to be very uniform and is continually monitored with nuclear magnetic resonance (NMR) probes. Detailed Muon Campus beamline and muon storage ring simulations are also required for quantifying beam dynamics and spin-related systematic effects in the determination of the muon anomalous precession frequency, e.g. muon losses during the measurement window. At the time of the conference, the experiment has recently commenced Run-3, and the release of Run-1 physics results is planned for 2020.