O mistério da matéria e antimatéria continua sem solução

terça-feira, janeiro 24, 2017

Sixfold improved single particle measurement of the magnetic moment of the antiproton

H. Nagahama, C. Smorra, S. Sellner, J. Harrington, T. Higuchi, M. J. Borchert, T. Tanaka, M. Besirli, A. Mooser, G. Schneider, K. Blaum, Y. Matsuda, C. Ospelkaus, W. Quint, J. Walz, Y. Yamazaki & S. Ulmer

Nature Communications 8, Article number: 14084 (2017)

Atomic and molecular physicsTheoretical physics

Received: 22 June 2016 Accepted: 28 November 2016 Published online: 18 January 2017

Figure 1: Experimental set-up and resonances.


Our current understanding of the Universe comes, among others, from particle physics and cosmology. In particle physics an almost perfect symmetry between matter and antimatter exists. On cosmological scales, however, a striking matter/antimatter imbalance is observed. This contradiction inspires comparisons of the fundamental properties of particles and antiparticles with high precision. Here we report on a measurement of the g-factor of the antiproton with a fractional precision of 0.8 parts per million at 95% confidence level. Our value /2=2.7928465(23) outperforms the previous best measurement by a factor of 6. The result is consistent with our proton g-factor measurement gp/2=2.792847350(9), and therefore agrees with the fundamental charge, parity, time (CPT) invariance of the Standard Model of particle physics. Additionally, our result improves coefficients of the standard model extension which discusses the sensitivity of experiments with respect to CPT violation by up to a factor of 20.

Additional information

How to cite this article: Nagahama, H. et al. Sixfold improved single particle measurement of the magnetic moment of the antiproton. Nat. Commun. 8, 14084 doi: 10.1038/ncomms14084 (2017).

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We acknowledge technical support by the Antiproton Decelerator group, CERN’s cryolab team, and all other CERN groups which provide support to Antiproton Decelerator experiments. We acknowledge financial support by RIKEN Initiative Research Unit Program, RIKEN President Funding, RIKEN Pioneering Project Funding, RIKEN FPR Funding, the RIKEN JRA Program, the Grant-in-Aid for Specially Promoted Research (no. 24000008) of MEXT, the Max-Planck Society, the EU (ERC Advanced Grant No. 290870-MEFUCO), the Helmholtz-Gemeinschaft, and the CERN-fellowship programme.

Author information


RIKEN, Ulmer Initiative Research Unit, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
H. Nagahama, C. Smorra, S. Sellner, T. Higuchi, T. Tanaka, M. Besirli, A. Mooser, G. Schneider & S. Ulmer
Graduate School of Arts and Sciences, University of Tokyo, Tokyo 153-8902, Japan
H. Nagahama, T. Higuchi, T. Tanaka & Y. Matsuda
CERN, CH-1211 Geneva 23, Switzerland
C. Smorra
Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
J. Harrington & K. Blaum
Institut für Quantenoptik, Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany
M. J. Borchert & C. Ospelkaus
Institut für Physik, Johannes Gutenberg-Universität, 55099 Mainz, Germany
G. Schneider & J. Walz
Physikalisch-Technische Bundesanstalt, QUEST, Bundesallee 100, 38116 Braunschweig, Germany
C. Ospelkaus
GSI-Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany
W. Quint
Helmholtz-Institut Mainz, sektion MAM, 55099 Mainz, Germany
J. Walz
RIKEN, Atomic Physics Research Unit, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
Y. Yamazaki


The experimental apparatus was developed and constructed by S.U., C.S., A.M., H.N., G.S., T.H. and S.S.; The experiment was commissioned by H.N., S.U., C.S. and S.S.; S.U. and C.S. developed the software system and experiment control. S.U., C.S., A.M., S.S., H.N., T.H., M.B., M.J.B. and T.T. participated in the 2015 antiproton run and contributed to the data-taking. S.U., H.N. and C.S. discussed and analysed the data. S.U. and H.N. performed the systematic studies and wrote the manuscript, which was then discussed and approved by all authors.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to H. Nagahama or S. Ulmer.