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Anderson EK, Baker CJ, Bertsche W, Bhatt NM, Bonomi G, Capra A, Carli I, Cesar CL, Charlton M, Christensen A, Collister R, Cridland Mathad A, Duque Quiceno D, Eriksson S, Evans A, Evetts N, Fabbri S, Fajans J, Ferwerda A, Friesen T, Fujiwara MC, Gill DR, Golino LM, Gomes Gonçalves MB, Grandemange P, Granum P, Hangst JS, Hayden ME, Hodgkinson D, Hunter ED, Isaac CA, Jimenez AJU, Johnson MA, Jones JM, Jones SA, Jonsell S, Khramov A, Madsen N, Martin L, Massacret N, Maxwell D, McKenna JTK, Menary S, Momose T, Mostamand M, Mullan PS, Nauta J, Olchanski K, Oliveira AN, Peszka J, Powell A, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Schoonwater J, Silveira DM, Singh J, Smith G, So C, Stracka S, Stutter G, Tharp TD, Thompson KA, Thompson RI, Thorpe-Woods E, Torkzaban C, Urioni M, Woosaree P, Wurtele JS. Observation of the effect of gravity on the motion of antimatter. Nature 2023; 621:716-722. [PMID: 37758891 PMCID: PMC10533407 DOI: 10.1038/s41586-023-06527-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 08/09/2023] [Indexed: 09/29/2023]
Abstract
Einstein's general theory of relativity from 19151 remains the most successful description of gravitation. From the 1919 solar eclipse2 to the observation of gravitational waves3, the theory has passed many crucial experimental tests. However, the evolving concepts of dark matter and dark energy illustrate that there is much to be learned about the gravitating content of the universe. Singularities in the general theory of relativity and the lack of a quantum theory of gravity suggest that our picture is incomplete. It is thus prudent to explore gravity in exotic physical systems. Antimatter was unknown to Einstein in 1915. Dirac's theory4 appeared in 1928; the positron was observed5 in 1932. There has since been much speculation about gravity and antimatter. The theoretical consensus is that any laboratory mass must be attracted6 by the Earth, although some authors have considered the cosmological consequences if antimatter should be repelled by matter7-10. In the general theory of relativity, the weak equivalence principle (WEP) requires that all masses react identically to gravity, independent of their internal structure. Here we show that antihydrogen atoms, released from magnetic confinement in the ALPHA-g apparatus, behave in a way consistent with gravitational attraction to the Earth. Repulsive 'antigravity' is ruled out in this case. This experiment paves the way for precision studies of the magnitude of the gravitational acceleration between anti-atoms and the Earth to test the WEP.
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Affiliation(s)
- E K Anderson
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - C J Baker
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - W Bertsche
- School of Physics and Astronomy, University of Manchester, Manchester, UK.
- Cockcroft Institute, Sci-Tech Daresbury, Warrington, UK.
| | - N M Bhatt
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - G Bonomi
- University of Brescia, Brescia and INFN Pavia, Pavia, Italy
| | - A Capra
- TRIUMF, Vancouver, British Columbia, Canada
| | - I Carli
- TRIUMF, Vancouver, British Columbia, Canada
| | - C L Cesar
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - M Charlton
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - A Christensen
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - R Collister
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - A Cridland Mathad
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - D Duque Quiceno
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - S Eriksson
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - A Evans
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - N Evetts
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - S Fabbri
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Accelerator and Technology Sector, CERN, Geneva, Switzerland
| | - J Fajans
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA.
| | - A Ferwerda
- Department of Physics and Astronomy, York University, Toronto, Ontario, Canada
| | - T Friesen
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | | | - D R Gill
- TRIUMF, Vancouver, British Columbia, Canada
| | - L M Golino
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - M B Gomes Gonçalves
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | | | - P Granum
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - J S Hangst
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark.
| | - M E Hayden
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada
| | - D Hodgkinson
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - E D Hunter
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - C A Isaac
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | | | - M A Johnson
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Cockcroft Institute, Sci-Tech Daresbury, Warrington, UK
| | - J M Jones
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - S A Jones
- Van Swinderen Institute for Particle Physics and Gravity, University of Groningen, Groningen, The Netherlands
| | - S Jonsell
- Department of Physics, Stockholm University, Stockholm, Sweden
| | - A Khramov
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Physics, British Columbia Institute of Technology, Burnaby, British Columbia, Canada
| | - N Madsen
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - L Martin
- TRIUMF, Vancouver, British Columbia, Canada
| | | | - D Maxwell
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - J T K McKenna
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
- School of Physics and Astronomy, University of Manchester, Manchester, UK
| | - S Menary
- Department of Physics and Astronomy, York University, Toronto, Ontario, Canada
| | - T Momose
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - M Mostamand
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - P S Mullan
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
- Institute for Particle Physics and Astrophysics, ETH, Zurich, Switzerland
| | - J Nauta
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | | | - A N Oliveira
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - J Peszka
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
- Institute for Particle Physics and Astrophysics, ETH, Zurich, Switzerland
| | - A Powell
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - C Ø Rasmussen
- Experimental Physics Department, CERN, Geneva, Switzerland
| | - F Robicheaux
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
| | - R L Sacramento
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - M Sameed
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Accelerator Systems Department, CERN, Geneva, Switzerland
| | - E Sarid
- Soreq NRC, Yavne, Israel
- Department of Physics, Ben Gurion University, Beer Sheva, Israel
| | - J Schoonwater
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - D M Silveira
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - J Singh
- School of Physics and Astronomy, University of Manchester, Manchester, UK
| | - G Smith
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - C So
- TRIUMF, Vancouver, British Columbia, Canada
| | | | - G Stutter
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
- School of Mathematical and Physical Sciences, University of Sussex, Brighton, UK
| | - T D Tharp
- Physics Department, Marquette University, Milwaukee, WI, USA
| | - K A Thompson
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - R I Thompson
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - E Thorpe-Woods
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - C Torkzaban
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - M Urioni
- University of Brescia, Brescia and INFN Pavia, Pavia, Italy
| | - P Woosaree
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - J S Wurtele
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
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Baker CJ, Bertsche W, Capra A, Cesar CL, Charlton M, Mathad AC, Eriksson S, Evans A, Evetts N, Fabbri S, Fajans J, Friesen T, Fujiwara MC, Grandemange P, Granum P, Hangst JS, Hayden ME, Hodgkinson D, Isaac CA, Johnson MA, Jones JM, Jones SA, Jonsell S, Kurchaninov L, Madsen N, Maxwell D, McKenna JTK, Menary S, Momose T, Mullan P, Olchanski K, Olin A, Peszka J, Powell A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, Stutter G, So C, Tharp TD, Thompson RI, van der Werf DP, Wurtele JS. Sympathetic cooling of positrons to cryogenic temperatures for antihydrogen production. Nat Commun 2021; 12:6139. [PMID: 34686658 PMCID: PMC8536749 DOI: 10.1038/s41467-021-26086-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 09/13/2021] [Indexed: 11/25/2022] Open
Abstract
The positron, the antiparticle of the electron, predicted by Dirac in 1931 and discovered by Anderson in 1933, plays a key role in many scientific and everyday endeavours. Notably, the positron is a constituent of antihydrogen, the only long-lived neutral antimatter bound state that can currently be synthesized at low energy, presenting a prominent system for testing fundamental symmetries with high precision. Here, we report on the use of laser cooled Be+ ions to sympathetically cool a large and dense plasma of positrons to directly measured temperatures below 7 K in a Penning trap for antihydrogen synthesis. This will likely herald a significant increase in the amount of antihydrogen available for experimentation, thus facilitating further improvements in studies of fundamental symmetries.
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Affiliation(s)
- C J Baker
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - W Bertsche
- School of Physics and Astronomy, University of Manchester, Manchester, M12 9PL, UK
- Cockcroft Institute, Sci-Tech Daresbury, Warrington, WA4 4AD, UK
| | - A Capra
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada
| | - C L Cesar
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-972, Brazil
| | - M Charlton
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - A Cridland Mathad
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - S Eriksson
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - A Evans
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - N Evetts
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1, Canada
| | - S Fabbri
- School of Physics and Astronomy, University of Manchester, Manchester, M12 9PL, UK
| | - J Fajans
- Department of Physics, University of California at Berkeley, Berkeley, CA, 94720-7300, USA
| | - T Friesen
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - M C Fujiwara
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada
| | - P Grandemange
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada
| | - P Granum
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark
| | - J S Hangst
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark
| | - M E Hayden
- Department of Physics, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada
| | - D Hodgkinson
- School of Physics and Astronomy, University of Manchester, Manchester, M12 9PL, UK
| | - C A Isaac
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - M A Johnson
- School of Physics and Astronomy, University of Manchester, Manchester, M12 9PL, UK
| | - J M Jones
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - S A Jones
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark
| | - S Jonsell
- Department of Physics, Stockholm University, SE-10691, Stockholm, Sweden
| | - L Kurchaninov
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada
| | - N Madsen
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK.
| | - D Maxwell
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK.
| | - J T K McKenna
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark
| | - S Menary
- Department of Physics and Astronomy, York University, Toronto, ON, M3J 1P3, Canada
| | - T Momose
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1, Canada
| | - P Mullan
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - K Olchanski
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada
| | - A Olin
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada
| | - J Peszka
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - A Powell
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - P Pusa
- Department of Physics, University of Liverpool, Liverpool, L69 7ZE, UK
| | - C Ø Rasmussen
- Experimental Physics Department, CERN, Geneva, 1211, Switzerland
| | - F Robicheaux
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, 47907, USA
| | - R L Sacramento
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-972, Brazil
| | - M Sameed
- School of Physics and Astronomy, University of Manchester, Manchester, M12 9PL, UK
| | - E Sarid
- Soreq NRC, 81800, Yavne, Israel
- Department of Physics, Ben Gurion University, 8410501, Beer Sheva, Israel
| | - D M Silveira
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-972, Brazil
| | - G Stutter
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark
| | - C So
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - T D Tharp
- Physics Department, Marquette University, P.O. Box 1881, Milwaukee, WI, 53201-1881, USA
| | - R I Thompson
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - D P van der Werf
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - J S Wurtele
- Department of Physics, University of California at Berkeley, Berkeley, CA, 94720-7300, USA
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