Analysis and Operations for the Precision Measurement of the Muon Anomaly

Grants and Contracts Details


Precision measurement of the muon anomalous magnetic moment We propose continuing research involving responsibilities for experiment operations, data ac- quisition, and data analysis on the Fermilab muon g-2 experiment. The Fermilab muon g-2 experiment aims to measure the muon anomalous magnetic moment aµ to 140 ppb, a four-fold improvement over the previous BNL experiment. The measurement addresses the longstanding 3.7σ discrepancy between the standard model prediction and the earlier BNL measurement. It is well recognized as a exacting test of the standard model with unique sensitivity to new particles, interactions and phenomena. The 140 ppb goal is commensurate with a world-wide theoretical e?ort to determine aµ that utilizes both new e+e− → hadrons data / analyses and lattice QCD+QED to determine the hadronic vacuum polarization and hadronic light-by-light contributions. The past three years have seen the completion of three production runs of the g-2 experiment; run 1 (March 18 - July 18) yielding 1.0× BNL statistics, run 2 (March 18-July 19) yielding 1.3× BNL statistics, and run 3 (December 19 - March 20) yielding 3.0× BNL statistics. The data quality was continually improved over the period of these runs including (i) reduction in the changes in the beam properties during the measurement period, (ii) reduction in experimental hall temperature changes and consequently calorimeter gain changes, and (iii) achieving the full high voltage kick of the incoming beam onto the storage ring central orbit. The stability of the pulsed quadrupoles, electrostatic kicker, and data acquisition and control systems were also continuously improved over the duration of these runs and achieved a 95% experimental uptime. The g-2 experiment – and our group – has a minium of 3-4 years of full-time operations / analysis in front of us. Run 4 (20 - 21) and run 5 (21 - 22) have been scheduled by the laboratory and are anticipated to yield additional 15× the BNL statistics. Further running - e.g. high statistics negative muon run - will presumably depend on whether the discrepancy between the current experimental value and SM predicted value is con?rmed or refuted. The laboratory is working on a fast kicker that will facilitate switching between g-2 and mu2e operations. The PI’s group – the PI, post-doc Ran Hong, and two PhD students – have leadership roles in both experimental operations and data analysis. The PI is an ωa analysis coordinator and organized the run 1 unblinding of the ωa analysis. The PI also led the development of the new energy- integrating approach to the ωa extraction and performed the run 1 energy-integrating ωa analysis. Our post-doc is the data acquisition system manager and was a run coordinator in run 3 and will be a run coordinator in run 4. Our postdoc also led the major upgrade of the g-2 data acquisition during the 2020 summer shutdown. Note the energy-integrating method for extracting ωa – which inherits very di?erent systematics compared to traditional positron reconstruction methods – has already born fruit in introducing new approaches to handling beam dynamics e?ects. Our PhD student Ritwika Chakraborty will complete her dissertation on the run 2 / 3 using the energy-intergrating method for extracting ωa. A new PhD student is being recruited to both contribute to our data collection responsibilities during run 4 / 5 and conduct their dissertation on run 4 / 5 using the energy-intergrating method for extracting ωa. Broader impact. The planned research includes substantial broader impact. The PI will continue his e?orts to involve high school students, computing, engineering and physics majors, and graduate students and post-docs in research activities. He will continue his e?orts to advance the quality and diversity of graduate studies in physics. The PI is continuing to develop written and video material in general physics that’s made available through Canvas Commons to others educators. Our activities in data acquisition and data analysis involve students in many aspects of modern computing such as parallel processing, computer networking, digital signal processing, telecommu- nication related hardware, various programming and scripting languages, and various scienti?c and mathematical packages. Our research will determine a textbook quantity with broad interest and high impact in nuclear, particle and astrophysics. 1
Effective start/end date9/1/218/31/25


  • National Science Foundation: $520,000.00


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