A Measurement of the Anomalous Magnetic Moment of the Negative Muon to 0.7 Ppm

The anomalous magnetic moment amu = ( g - 2)/2 of the negative muon has been measured to 0.7 ppm in an experiment at Brookhaven National Laboratory. Prior data runs at Brookhaven were taken with the positive muon, so this constitutes the first improved measurement of the negative muon's magnetic moment since the CERN experiments of the 1970's. The result from the Brookhaven experiment for the negative muon is aexpm-=11659214 8x10-10, which is in good agreement with the CERN value of aCERNu- = 11659370(120) x 10-10. The world average for the positive muon is dominated by Brookhaven experiments with a value of aexpm+=11659203 8x10-10. The difference between the positive and negative magnetic moments, Dam=aexp m--aexpm +=1111x1 0-10, is statistically acceptable. Invoking CPT and combining the results for both charge species yields aexpm=11659208 6x10-100. 5ppm. At this precision, amu is sensitive to virtual loops from the electroweak sector and probes the contribution from the hadronic sector at the 1% level. The current prediction from the standard model is, athym=11659182.4 7.2x10-10 0.6ppm, where the error is dominated by uncertainties in the hadronic calculation. The standard model prediction and the experimental result differ at the 2.7sigma level. This difference is suggestive of physics beyond the standard model, although not conclusive. The magnitude of the difference is compatible with certain supersymmetric models and can be use to set constraints on many exotic physics models including muon substructure, permanent electric dipole moments, and others. This thesis presents a complete description of the experiment including a novel technique for analyzing the g - 2 precession frequency, in which the data from high-energy decay electrons are preferentially weighted in the fit.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Polly, Charles C.

Contributors dc:contributor

• Hertzog, David W.

• Physics, Nuclear

Language dc:language

eng

Identifier

(MiAaPQ)AAI3199116

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/80523