BASE (Baryon Antibaryon Symmetry Experiment), AD-8, is a multinational collaboration at the Antiproton Decelerator facility at CERN, Geneva. The goal of the Japanese and German BASE collaboration[1] are high-precision investigations of the fundamental properties of the antiproton, namely the charge-to-mass ratio and the magnetic moment.
| ELENA | Extra low energy antiproton ring – further decelerates antiprotons coming from AD |
|---|---|
| AD experiments | |
| ATHENA | AD-1 Antihydrogen production and precision experiments |
| ATRAP | AD-2 Cold antihydrogen for precise laser spectroscopy |
| ASACUSA | AD-3 Atomic spectroscopy and collisions with antiprotons |
| ACE | AD-4 Antiproton cell experiment |
| ALPHA | AD-5 Antihydrogen laser physics apparatus |
| AEgIS | AD-6 Antihydrogen experiment gravity interferometry spectroscopy |
| GBAR | AD-7 Gravitational behaviour of anti-hydrogen at rest |
| BASE | AD-8 Baryon antibaryon symmetry experiment |
| PUMA | AD-9 Antiproton unstable matter annihilation |
Experimental setup
editThe single antiprotons are stored in an advanced Penning trap system, which has a multi-trap system at its core. It consists of a reservoir trap,[2] a precision trap, an analysis trap and a cooling trap. The reservoir trap has the capability to store antiprotons for several years[3] and allows BASE to operate experiments independent from accelerator cycles. The precision trap is for high precision frequency measurements, and the analysis trap has a strong magnetic field inhomogeneity superimposed, which is used for single particle spin flip spectroscopy. By measuring the spin flip rate as a function of the frequency of an externally applied magnetic-drive, a resonance curve is obtained. Together with a measurement of the cyclotron frequency, the magnetic moment is extracted.
BASE physics
editThe BASE collaboration developed techniques to observe the first spin flips of a single trapped proton[4] and applied the double-trap technique to measure the magnetic moment of the proton with a fractional precision of three parts in a billion,[5] later improved to a precision of 300 parts in a trillion, [6] being the most precise measurement of this fundamental property of the proton. With the invention of a two particle/three trap technique BASE measured the antiproton magnetic moment with a fractional accuracy of 1.5 parts in a billion, which improved the previous most precise proton/antiproton comparison in that sector [7] by more than a factor of 3000. This measurement constitutes one of the most stringent tests of CPT invariance with baryons to date, and sets the most stringent limits on antimatter/dark matter interaction to date.[8]
Inspired by this work BASE has also used Penning trap detectors as axion haloscopes, and derived stringent narrow-band laboratory limits on the conversion of axions to photons.[9]
In 2022 BASE measured that the charge-to-mass ratios of protons and antiprotons are equal within a precision of 16 parts per trillion.[10][11] This measurement constitutes the most precise test of CPT invariance in the baryon sector and sets the first differential constraints on the clock weak equivalence principle using baryonic antimatter.
BASE collaboration
edit
The BASE collaboration comprises the following institutions:
- RIKEN, Japan
- University of Tokyo, Japan
- Max Planck Institute for Nuclear Physics, Germany
- University of Mainz, Germany
- GSI, Germany
- Leibniz University Hannover, Germany
- PTB, Braunschweig, Germany
- ETH Zürich, Switzerland
See also
editReferences
edit- ^ "official BASE website".
- ^ Smorra, C.; Mooser, A.; Franke, K.; Nagahama, H.; Schneider, G.; Higuchi, T.; Gorp, S. V.; Blaum, K.; Matsuda, Y.; Quint, W.; Walz, J.; Yamazaki, Y.; Ulmer, S. (2015-10-15). "A reservoir trap for antiprotons". International Journal of Mass Spectrometry. 389: 10–13. arXiv:1507.04147. Bibcode:2015IJMSp.389...10S. doi:10.1016/j.ijms.2015.08.007. ISSN 1387-3806. S2CID 106405164.
- ^ Sellner, S; Besirli, M; Bohman, M; Borchert, M J; Harrington, J; Higuchi, T; Mooser, A; Nagahama, H; Schneider, G; Smorra, C; Tanaka, T; Blaum, K; Matsuda, Y; Ospelkaus, C; Quint, W (2017-08-31). "Improved limit on the directly measured antiproton lifetime". New Journal of Physics. 19 (8): 083023. Bibcode:2017NJPh...19h3023S. doi:10.1088/1367-2630/aa7e73. ISSN 1367-2630. S2CID 125095370.
- ^ Ulmer, S.; et al. (20 June 2011). "Observation of Spin Flips with a Single Trapped Proton". Physical Review Letters. 106 (25): 253001. arXiv:1104.1206. Bibcode:2011PhRvL.106y3001U. doi:10.1103/PhysRevLett.106.253001. PMID 21770638. S2CID 13997553.
- ^ Mooser, A.; et al. (2014). "Direct high-precision measurement of the magnetic moment of the proton". Nature. 509 (7502): 596–599. arXiv:1406.4888. Bibcode:2014Natur.509..596M. doi:10.1038/nature13388. PMID 24870545. S2CID 4463940.
- ^ Schneider, Georg; Mooser, Andreas; Bohman, Matthew; Schön, Natalie; Harrington, James; Higuchi, Takashi; Nagahama, Hiroki; Sellner, Stefan; Smorra, Christian; Blaum, Klaus; Matsuda, Yasuyuki; Quint, Wolfgang; Walz, Jochen; Ulmer, Stefan (2017-11-24). "Double-trap measurement of the proton magnetic moment at 0.3 parts per billion precision". Science. 358 (6366): 1081–1084. Bibcode:2017Sci...358.1081S. doi:10.1126/science.aan0207. ISSN 0036-8075. PMID 29170238. S2CID 206658547.
- ^ ATRAP Collaboration; DiSciacca, J.; Marshall, M.; Marable, K.; Gabrielse, G.; Ettenauer, S.; Tardiff, E.; Kalra, R.; Fitzakerley, D. W.; George, M. C.; Hessels, E. A.; Storry, C. H.; Weel, M.; Grzonka, D.; Oelert, W. (2013-03-25). "One-Particle Measurement of the Antiproton Magnetic Moment". Physical Review Letters. 110 (13): 130801. arXiv:1301.6310. Bibcode:2013PhRvL.110m0801D. doi:10.1103/PhysRevLett.110.130801. PMID 23581304. S2CID 14943420.
- ^ ATRAP Collaboration; DiSciacca, J.; Marshall, M.; Marable, K.; Gabrielse, G.; Ettenauer, S.; Tardiff, E.; Kalra, R.; Fitzakerley, D. W.; George, M. C.; Hessels, E. A.; Storry, C. H.; Weel, M.; Grzonka, D.; Oelert, W. (2013-03-25). "One-Particle Measurement of the Antiproton Magnetic Moment". Physical Review Letters. 110 (13): 130801. arXiv:1301.6310. Bibcode:2013PhRvL.110m0801D. doi:10.1103/PhysRevLett.110.130801. PMID 23581304. S2CID 14943420.
- ^ Devlin, Jack A.; Borchert, Matthias J.; Erlewein, Stefan; Fleck, Markus; Harrington, James A.; Latacz, Barbara; Warncke, Jan; Wursten, Elise; Bohman, Matthew A.; Mooser, Andreas H.; Smorra, Christian; Wiesinger, Markus; Will, Christian; Blaum, Klaus; Matsuda, Yasuyuki (2021-01-25). "Constraints on the Coupling between Axionlike Dark Matter and Photons Using an Antiproton Superconducting Tuned Detection Circuit in a Cryogenic Penning Trap". Physical Review Letters. 126 (4): 041301. arXiv:2101.11290. Bibcode:2021PhRvL.126d1301D. doi:10.1103/PhysRevLett.126.041301. PMID 33576660. S2CID 231719186.
- ^ Borchert, M. J.; Devlin, J. A.; Erlewein, S. R.; Fleck, M.; Harrington, J. A.; Higuchi, T.; Latacz, B. M.; Voelksen, F.; Wursten, E. J.; Abbass, F.; Bohman, M. A. (2022-01-06). "A 16-parts-per-trillion measurement of the antiproton-to-proton charge–mass ratio". Nature. 601 (7891): 53–57. Bibcode:2022Natur.601...53B. doi:10.1038/s41586-021-04203-w. ISSN 0028-0836. PMID 34987217. S2CID 256822230.
- ^ "BASE breaks new ground in matter–antimatter comparisons". CERN. Retrieved 2022-01-14.
External links
editRecord for BASE Experiment on INSPIRE-HEP