A 16-parts-per-trillion measurement of the antiproton-to-proton charge–mass ratio

authored by: M. J. Borchert, J. A. Devlin, S. R. Erlewein, M. Fleck, J. A. Harrington, T. Higuchi, B. M. Latacz, F. Voelksen, E. J. Wursten, F. Abbass, M. A. Bohman, A. H. Mooser, D. Popper, M. Wiesinger, C. Will, K. Blaum, Y. Matsuda, C. Ospelkaus, W. Quint, J. Walz, Y. Yamazaki, C. Smorra, S. Ulmer
Abstract: The standard model of particle physics is both incredibly successful and glaringly incomplete. Among the questions left open is the striking imbalance of matter and antimatter in the observable universe¹, which inspires experiments to compare the fundamental properties of matter/antimatter conjugates with high precision^2–5. Our experiments deal with direct investigations of the fundamental properties of protons and antiprotons, performing spectroscopy in advanced cryogenic Penning trap systems⁶. For instance, we previously compared the proton/antiproton magnetic moments with 1.5 parts per billion fractional precision^7,8, which improved upon previous best measurements⁹ by a factor of greater than 3,000. Here we report on a new comparison of the proton/antiproton charge-to-mass ratios with a fractional uncertainty of 16 parts per trillion. Our result is based on the combination of four independent long-term studies, recorded in a total time span of 1.5 years. We use different measurement methods and experimental set-ups incorporating different systematic effects. The final result, − (q/ m) _p/ (q/ m) _p¯= 1.000000000003 (16) , is consistent with the fundamental charge–parity–time reversal invariance, and improves the precision of our previous best measurement⁶ by a factor of 4.3. The measurement tests the standard model at an energy scale of 1.96 × 10⁻²⁷ gigaelectronvolts (confidence level 0.68), and improves ten coefficients of the standard model extension¹⁰. Our cyclotron clock study also constrains hypothetical interactions mediating violations of the clock weak equivalence principle (WEP_cc) for antimatter to less than 1.8 × 10⁻⁷, and enables the first differential test of the WEP_cc using antiprotons¹¹. From this interpretation we constrain the differential WEP_cc-violating coefficient to less than 0.030.
Organisation(s): Institute of Quantum Optics
QuantumFrontiers
CRC 1227 Designed Quantum States of Matter (DQ-mat)
External Organisation(s): Ulmer Fundamental Symmetries Laboratory
National Metrology Institute of Germany (PTB)
CERN
Max Planck Institute for Nuclear Physics
University of Tokyo
GSI Helmholtz Centre for Heavy Ion Research
Johannes Gutenberg University Mainz
Type: Article
Journal: NATURE
Volume: 601
Pages: 53-57
No. of pages: 5
ISSN: 0028-0836
Publication date: 06.01.2022
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: General
Electronic version(s): https://doi.org/10.1038/s41586-021-04203-w (Access: Closed)

BibTeX

@article{9ce0101313414261bcafc206aa670015,
title = "A 16-parts-per-trillion measurement of the antiproton-to-proton charge–mass ratio",
abstract = "The standard model of particle physics is both incredibly successful and glaringly incomplete. Among the questions left open is the striking imbalance of matter and antimatter in the observable universe1, which inspires experiments to compare the fundamental properties of matter/antimatter conjugates with high precision2–5. Our experiments deal with direct investigations of the fundamental properties of protons and antiprotons, performing spectroscopy in advanced cryogenic Penning trap systems6. For instance, we previously compared the proton/antiproton magnetic moments with 1.5 parts per billion fractional precision7,8, which improved upon previous best measurements9 by a factor of greater than 3,000. Here we report on a new comparison of the proton/antiproton charge-to-mass ratios with a fractional uncertainty of 16 parts per trillion. Our result is based on the combination of four independent long-term studies, recorded in a total time span of 1.5 years. We use different measurement methods and experimental set-ups incorporating different systematic effects. The final result, − (q/ m) p/ (q/ m) p¯= 1.000000000003 (16) , is consistent with the fundamental charge–parity–time reversal invariance, and improves the precision of our previous best measurement6 by a factor of 4.3. The measurement tests the standard model at an energy scale of 1.96 × 10−27 gigaelectronvolts (confidence level 0.68), and improves ten coefficients of the standard model extension10. Our cyclotron clock study also constrains hypothetical interactions mediating violations of the clock weak equivalence principle (WEPcc) for antimatter to less than 1.8 × 10−7, and enables the first differential test of the WEPcc using antiprotons11. From this interpretation we constrain the differential WEPcc-violating coefficient to less than 0.030.",
author = "Borchert, {M. J.} and Devlin, {J. A.} and Erlewein, {S. R.} and M. Fleck and Harrington, {J. A.} and T. Higuchi and Latacz, {B. M.} and F. Voelksen and Wursten, {E. J.} and F. Abbass and Bohman, {M. A.} and Mooser, {A. H.} and D. Popper and M. Wiesinger and C. Will and K. Blaum and Y. Matsuda and C. Ospelkaus and W. Quint and J. Walz and Y. Yamazaki and C. Smorra and S. Ulmer",
note = "Funding Information: This work was supported by the Max Planck, RIKEN, PTB Center for Time, Constants, and Fundamental Symmetries (C-TCFS). Funding Information: Acknowledgements We acknowledge technical support by CERN, especially the Antiproton Decelerator operation group, CERN{\textquoteright}s cryolab team and engineering department, and all other CERN groups that provide support to Antiproton Decelerator experiments. We acknowledge Y. Ding for comments in the discussion of the updated SME limits. We acknowledge financial support by RIKEN, the RIKEN EEE pioneering project funding, the RIKEN SPDR and JRA programme, the Max Planck Society, the European Union (FunI-832848, STEP-852818), CRC 1227 {\textquoteleft}DQ-mat{\textquoteright}(DFG 274200144), the Cluster of Excellence {\textquoteleft}Quantum Frontiers{\textquoteright} (DFG 390837967), AVA-721559, the CERN fellowship programme and the Helmholtz-Gemeinschaft.",
year = "2022",
month = jan,
day = "6",
doi = "10.1038/s41586-021-04203-w",
language = "English",
volume = "601",
pages = "53--57",
journal = "NATURE",
issn = "0028-0836",
publisher = "Nature Publishing Group",
number = "7891",
}