Measuring the anomalous precession frequency of the muon in run 2 of the Fermilab muon g-2 experiment

Abstract

The E989 Muon g −2 Experiment at Fermilab aims to measure the anomalous magnetic moment of the muon, aμ, to an unprecedented precision of 140 parts per billion (ppb). Currently, a 4.2σ discrepancy exists between the experimental value of aμ and the theoretical value given by the Standard Model. The goal of E989 is to either confirm this discrepancy and suggest new physics, or show the discrepancy to be an error. The first result from E989 has been published [1], using data collected during Run 1, which confirms the tension between theory and experiment. A total of 5 runs are planned, increasing the amount of data by roughly a factor of 10. This thesis outlines the history, motivations, and physics of the E989 experiment, and presents a preliminary analysis of data collected during Run 2.

Determining aμ requires a precision measurement of two main quantities: (1) the anomalous precession frequency of muons in a magnetic storage ring and (2) the magnetic field experienced by those muons. The anomalous precession frequency, ωa must be measured with a systematic uncertainty below 70ppb in order for the collaboration to achieve its target precision. The analysis presented here concerns ωa.