Analysis and Operations for the Precision Measurement of the Muon Anomaly

University Of Kentucky Research Foundation, Lexington KY

Investigators

Abstract

This award supports research by the PI with the muon g-2 experiment at Fermi National Accelerator Facility in Chicago, Illinois. The goal of the experiment is a precision measurement of the anomalous response of the muon to a strong magnetic field. The anomalous magnetic moment of the muon comes from the `quantum foam' of virtual particles that exists in empty space. The anomaly can be measured precisely and the exact result addresses an intriguing discrepancy between prior measurements and the theoretical calculation of the muon's anomalous magnetism - a discrepancy that hints at unknown forces or new particles of nature. The PI group's responsibilities within the experiment are the operation and maintenance of the experiment's data acquisition system and the data analysis for the extraction of the muon anomalous precession frequency - the measured quantity that determines the anomalous magnetism. The award provides a broader impact through the involvement and training of high school students, physics majors, graduate students and post-doctoral researchers. The group's involvement in large-scale data acquisition, analysis and modeling also exposes students to innovative computer and telecommunications technologies. Moreover, the experiment itself - involving a precision measurement of a textbook quantity - will have a broad impact and a lasting legacy in nuclear, particle and astrophysics. The muon g-2 experiment will measure the muon anomalous magnetic moment to 140 parts-per-billion; a four-fold improvement over the prior BNL E821 experiment. The measurement will address the longstanding ~3.6 standard deviation discrepancy between the previous BNL E821 measurement and the Standard Model prediction. It represents a key test of the Standard Model of Physics and has broad sensitivity to new interactions, particles and phenomenon beyond the Standard Model. The first data taking run took place from November, 2017 through July, 2018 and was published in April, 2021. This initial 460 part-per-billion measurement is in agreement with the earlier 540 part-per-billion result from the BNL E821 experiment and increased the discrepancy between experiment and standard model to 4.2 standard deviations. The team expects a factor of two improvement from the data collected in runs that have not yet been analyzed and a factor of four improvement from future runs of the experiment. This award will support continuing research involving activities in experimental operations, data acquisition and data analysis on the Fermilab g-2 experiment. The PI's group is responsible for the development and the operation of the 20 GByte/sec, 100 TFlop, g-2 data readout and processing system and its upgrades. The PI's group is also responsible for the integrated energy analysis of the muon anomalous precession frequency. This new technique for extracting the frequency uses different raw data, applies different reconstruction procedures, and inherits different systematic uncertainties, in comparison to the traditional positron counting approaches and is important to the demonstration of the robustness of the frequency measurement. Lastly, the PI will continue his overall leadership in the anomalous frequency team as an analysis coordinator. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.