One-Particle Measurement of the Antiproton Magnetic Moment

ATRAP Collaboration; J. DiSciacca; M. Marshall; K. Marable; G. Gabrielse; S. Ettenauer; E. Tardiff; R. Kalra; D. W. Fitzakerley; M. C. George; E. A. Hessels; C. H. Storry; M. Weel; D. Grzonka; W. Oelert; T. Sefzick

arXiv · 1301.6310

One-Particle Measurement of the Antiproton Magnetic Moment

ATRAP Collaboration·J. DiSciacca·M. Marshall·K. Marable·G. Gabrielse·S. Ettenauer·E. Tardiff·R. Kalra·D. W. Fitzakerley·M. C. George·E. A. Hessels·C. H. Storry·M. Weel·D. Grzonka·W. Oelert·T. Sefzick

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Abstract

\DeclareRobustCommand{\pbar}{\HepAntiParticle{p}{}{}\xspace} \DeclareRobustCommand{\p}{\HepParticle{p}{}{}\xspace} \DeclareRobustCommand{\mup}{$\mu_{p}${}{}\xspace} \DeclareRobustCommand{\mupbar}{$\mu_{\pbar}${}{}\xspace} \DeclareRobustCommand{\muN}{$\mu_N${}{}\xspace For the first time a single trapped \pbar is used to measure the \pbar magnetic moment ${\bm\mu}_{\pbar}$. The moment ${\bm\mu}_{\pbar} = \mu_{\pbar} {\bm S}/(\hbar/2)$ is given in terms of its spin ${\bm S}$ and the nuclear magneton (\muN) by $\mu_{\pbar}/\mu_N = -2.792\,845 \pm 0.000\,012$. 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 $\mu_{\pbar}/\mu_p = -1.000\,000 \pm 0.000\,005$ to 5 ppm, for a proton moment ${\bm{\mu}}_{p} = \mu_{p} {\bm S}/(\hbar/2)$, consistent with the prediction of the CPT theorem.

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ATRAP Collaboration, J. DiSciacca, M. Marshall, K. Marable, G. Gabrielse, S. Ettenauer, E. Tardiff, R. Kalra, D. W. Fitzakerley, M. C. George, E. A. Hessels, C. H. Storry, M. Weel, D. Grzonka, W. Oelert, T. Sefzick. 2013-01-27. One-Particle Measurement of the Antiproton Magnetic Moment. https://arxiv.org/abs/1301.6310

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