反物質は地球を包み込み、通常の物質のように下へ落ちていく(Antimatter embraces Earth, falling downward like normal matter)

2023-09-27 カリフォルニア大学バークレー校(UCB)

＜関連情報＞

• https://news.berkeley.edu/2023/09/27/antimatter-embraces-earth-falling-downward-like-normal-matter
• https://www.nature.com/articles/s41586-023-06527-1

反物質の運動に対する重力の影響を観測 Observation of the effect of gravity on the motion of antimatter

E. K. Anderson,C. J. Baker,W. Bertsche,N. M. Bhatt,G. Bonomi,A. Capra,I. Carli,C. L. Cesar,M. Charlton,A. Christensen,R. Collister,A. Cridland Mathad,D. Duque Quiceno,S. Eriksson,A. Evans,N. Evetts,S. Fabbri,J. Fajans,A. Ferwerda,T. Friesen,M. C. Fujiwara,D. R. Gill,L. M. Golino,M. B. Gomes Gonçalves,P. Grandemange,P. Granum,J. S. Hangst,M. E. Hayden,D. Hodgkinson,E. D. Hunter,C. A. Isaac,A. J. U. Jimenez,M. A. Johnson,J. M. Jones,S. A. Jones,S. Jonsell,A. Khramov,N. Madsen,L. Martin,N. Massacret,D. Maxwell,J. T. K. McKenna,S. Menary,T. Momose,M. Mostamand,P. S. Mullan,J. Nauta,K. Olchanski,A. N. Oliveira,J. Peszka,A. Powell,C. Ø. Rasmussen,F. Robicheaux,R. L. Sacramento,M. Sameed,E. Sarid,J. Schoonwater,D. M. Silveira,J. Singh,G. Smith,C. So,S. Stracka,G. Stutter,T. D. Tharp,K. A. Thompson,R. I. Thompson,E. Thorpe-Woods,C. Torkzaban,M. Urioni,P. Woosaree & J. S. Wurtele
Nature  Published:27 September 2023
DOI:https://doi.org/10.1038/s41586-023-06527-1

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 matter^7,8,9,10. 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.