Limit on the electric charge of antihydrogen

A. Capra, C. Amole, M. D. Ashkezari, M. Baquero-Ruiz, W. Bertsche, E. Butler, C. L. Cesar, M. Charlton, S. Eriksson, J. Fajans, T. Friesen, M. C. Fujiwara, D. R. Gill, A. Gutierrez, J. S. Hangst, W. N. Hardy, M. E. Hayden, C. A. Isaac, S. Jonsell, L. KurchaninovA. Little, J. T. K. McKenna, S. Menary, S. C. Napoli, P. Nolan, K. Olchanski, A. Olin, A. Povilus, P. Pusa, F. Robicheaux, E. Sarid, D. M. Silveira, C. So, T. D. Tharp, R. I. Thompson, D. P. van der Werf, Z. Vendeiro, J. S. Wurtele, A. I. Zhmoginov, A. E. Charman

Research output: Contribution to journalArticlepeer-review


The ALPHA collaboration has successfully demonstrated the production and the confinement of cold antihydrogen, H̅. An analysis of trapping data allowed a stringent limit to be placed on the electric charge of the simplest antiatom. Charge neutrality of matter is known to a very high precision, hence a neutrality limit of H̅ provides a test of CPT invariance. The experimental technique is based on the measurement of the deflection of putatively charged H̅ in an electric field. The tendency for trapped H̅ atoms to be displaced by electrostatic fields is measured and compared to the results of a detailed simulation of H̅ dynamics in the trap. An extensive survey of the systematic errors was performed, and this work focuses on those due to the silicon vertex detector, which is the device used to determine the H̅ annihilation position. The limit obtained on the charge of the H̅ atom is Q = (−1.3 ± 1.8 ± 0.4) × 10−8, representing the first precision measurement with H̅ [1].

Original languageEnglish
Article number9
JournalHyperfine Interactions
Issue number1
StatePublished - 1 Nov 2017
Externally publishedYes


  • Antihydrogen
  • Atom trapping
  • CPT
  • Electric charge
  • Electric neutrality
  • Fundamental symmetries
  • Position sensitive detector
  • Quantum anomaly
  • Silicon detector

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Nuclear and High Energy Physics
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry


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