One-particle measurement of the antiproton magnetic moment

Abstract

For the first time a single trapped antiproton (p̄) is used to measure the p̄ magnetic moment μp̄. The moment μp̄=μp̄S/(/2) is given in terms of its spin S and the nuclear magneton (μN) by μp̄/ μN=-2.792 845±0.000 012. The 4.4 parts per million (ppm) uncertainty is 680 times smaller than previously realized. Comparing to the proton moment measured using the same method and trap electrodes gives μp̄/μp=-1.000 000±0.000 005 to 5 ppm, for a proton moment μp=μpS/(/2), consistent with the prediction of the CPT theorem. Published by the American Physical Society under the terms of the