002710810 001__ 2710810
002710810 003__ SzGeCERN
002710810 005__ 20220630134810.0
002710810 0247_ $$2DOI$$a10.1038/s41586-020-2006-5
002710810 0248_ $$aoai:inspirehep.net:1781389$$pcerncds:CERN:FULLTEXT$$pcerncds:FULLTEXT$$pcerncds:CERN$$qINSPIRE:HEP$$qForCDS
002710810 035__ $$9http://inspirehep.net/oai2d$$aoai:inspirehep.net:1781389$$d2020-02-21T16:24:04Z$$h2020-02-22T05:00:07Z$$mmarcxml
002710810 035__ $$9Inspire$$a1781389
002710810 041__ $$aeng
002710810 100__ $$aAhmadi, M$$uLiverpool U.
002710810 245__ $$9submitter$$aInvestigation of the fine structure of antihydrogen
002710810 260__ $$c2020
002710810 300__ $$a10 p
002710810 520__ $$9submitter$$aAt the historic Shelter Island Conference on the Foundations of Quantum Mechanics in 1947, Willis Lamb reported an unexpected feature in the fne structure of atomic hydrogen: a separation of the 2S$_{1/2}$ and 2P$_{1/2}$ states1. The observation of this separation, now known as the Lamb shift, marked an important event in the evolution of modern physics, inspiring others to develop the theory of quantum electrodynamics2–5. Quantum electrodynamics also describes antimatter, but it has only recently become possible to synthesize and trap atomic antimatter to probe its structure. Mirroring the historical development of quantum atomic physics in the twentieth century, modern measurements on anti-atoms represent a unique approach for testing quantum electrodynamics and the foundational symmetries of the standard model. Here we report measurements of the fne structure in the $n=$ 2 states of antihydrogen, the antimatter counterpart of the hydrogen atom. Using optical excitation of the 1S–2P Lyman-α transitions in antihydrogen6 , we determine their frequencies in a magnetic feld of 1 tesla to a precision of 16 parts per billion. Assuming the standard Zeeman and hyperfne interactions, we infer the zero-feld fne-structure splitting (2P$_{1/2}$–2P$_{3/2}$) in antihydrogen. The resulting value is consistent with the predictions of quantum electrodynamics to a precision of 2 per cent. Using our previously measured value of the 1S–2S transition frequency6,7, we fnd that the classic Lamb shift in antihydrogen (2S$_{1/2}$–2P$_{1/2}$ splitting at zero feld) is consistent with theory at a level of 11 per cent. Our observations represent an important step towards precision measurements of the fne structure and the Lamb shift in the antihydrogen spectrum as tests of the charge– parity–time symmetry8 and towards the determination of other fundamental quantities, such as the antiproton charge radius9,10, in this antimatter system.
002710810 540__ $$3publication$$aCC-BY-4.0$$uhttp://creativecommons.org/licenses/by/4.0/
002710810 542__ $$3publication$$dThe Authors$$g2020
002710810 595__ $$aFor annual report
002710810 65017 $$2SzGeCERN$$aParticle Physics - Experiment
002710810 690C_ $$aCERN
002710810 693__ $$eCERN ALPHA
002710810 700__ $$aAlves, B X R$$uAarhus U.
002710810 700__ $$aBaker, C J$$uSwansea U.
002710810 700__ $$aBertsche, W$$uManchester U.$$uCockcroft Inst. Accel. Sci. Tech.$$vCockcroft Institute, Warrington, UK.
002710810 700__ $$aCapra, A$$uTRIUMF
002710810 700__ $$aCarruth, C$$uUC, Berkeley
002710810 700__ $$aCesar, C L$$uRio de Janeiro Federal U.
002710810 700__ $$aCharlton, M$$uSwansea U.
002710810 700__ $$aCohen, S$$uBen Gurion U. of Negev
002710810 700__ $$aCollister, R$$uTRIUMF
002710810 700__ $$aEriksson, S$$uSwansea U.
002710810 700__ $$aEvans, A$$uCalgary U.
002710810 700__ $$aEvetts, N$$uBritish Columbia U.
002710810 700__ $$aFajans, J$$uUC, Berkeley
002710810 700__ $$aFriesen, T$$uAarhus U.$$uCalgary U.$$vDepartment of Physics and Astronomy, University of Calgary, Calgary, Alberta,Canada.
002710810 700__ $$aFujiwara, M [email protected]$$uTRIUMF
002710810 700__ $$aGill, D R$$uTRIUMF
002710810 700__ $$aGranum, P$$uAarhus U.
002710810 700__ $$aHangst, J [email protected]$$uAarhus U.
002710810 700__ $$aHardy, W N$$uBritish Columbia U.
002710810 700__ $$aHayden, M E$$uSimon Fraser U.
002710810 700__ $$aHunter, E D$$uUC, Berkeley
002710810 700__ $$aIsaac, C A$$uSwansea U.
002710810 700__ $$aJohnson, M A$$uManchester U.$$uCockcroft Inst. Accel. Sci. Tech.$$vCockcroft Institute, Warrington, UK.
002710810 700__ $$aJones, J M$$uSwansea U.
002710810 700__ $$aJones, S A$$uAarhus U.$$uSwansea U.$$vDepartment of Physics, College of Science, Swansea University, Swansea, UK.
002710810 700__ $$aJonsell, S$$uStockholm U.
002710810 700__ $$aKhramov, A$$uTRIUMF$$uBritish Columbia U.$$vDepartment of Physics and Astronomy, University of British Columbia, Vancouver,British Columbia, Canada.
002710810 700__ $$aKnapp, P$$uSwansea U.
002710810 700__ $$aKurchaninov, L$$uTRIUMF
002710810 700__ $$aMadsen, N$$uSwansea U.
002710810 700__ $$aMaxwell, D$$uSwansea U.
002710810 700__ $$aMcKenna, J T K$$uAarhus U.$$uTRIUMF$$vTRIUMF, Vancouver,British Columbia, Canada.
002710810 700__ $$aMenary, S$$uYork U., Canada
002710810 700__ $$aMichan, J M$$uTRIUMF$$uEPFL-ISIC, Lausanne$$vÉcole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), Lausanne,Switzerland.
002710810 700__ $$aMomose, [email protected]$$uBritish Columbia U.$$uBritish Columbia U.$$vDepartment of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada.
002710810 700__ $$aMunich, J J$$uSimon Fraser U.
002710810 700__ $$aOlchanski, K$$uTRIUMF
002710810 700__ $$aOlin, A$$uTRIUMF$$uVictoria U.$$vDepartment of Physics and Astronomy, University of Victoria, Victoria,British Columbia, Canada.
002710810 700__ $$aPusa, P$$uLiverpool U.
002710810 700__ $$aRasmussen, C Ø$$uAarhus U.
002710810 700__ $$aRobicheaux, F$$uPurdue U.
002710810 700__ $$aSacramento, R L$$uRio de Janeiro Federal U.
002710810 700__ $$aSameed, M$$uManchester U.
002710810 700__ $$aSarid, E$$uSoreq Nucl. Res. Ctr.
002710810 700__ $$aSilveira, D M$$uRio de Janeiro Federal U.
002710810 700__ $$aSo, C$$uTRIUMF$$uCalgary U.$$vDepartment of Physics and Astronomy, University of Calgary, Calgary, Alberta,Canada.
002710810 700__ $$aStarko, D M$$uYork U., Canada
002710810 700__ $$aStutter, G$$uAarhus U.
002710810 700__ $$aTharp, T D$$uSoreq Nucl. Res. Ctr.$$uMarquette U.$$vPhysics Department, Marquette University,Milwaukee, WI, USA.
002710810 700__ $$aThompson, R I$$uTRIUMF$$uCalgary U.$$vDepartment of Physics and Astronomy, University of Calgary, Calgary, Alberta,Canada.
002710810 700__ $$avan der Werf, D P$$uSwansea U.$$uIRFU, Saclay$$vIRFU, CEA/Saclay, Gif-sur-Yvette, France.
002710810 700__ $$aWurtele, J S$$uUC, Berkeley
002710810 710__ $$gALPHA Collaboration
002710810 773__ $$c375-380$$pNature$$v578$$y2020
002710810 8564_ $$uhttps://www.interactions.org/press-release/alpha-collaboration-cern-reports-first-measurements-certain$$yINTERACTIONS
002710810 8564_ $$uhttps://www.nature.com/articles/d41586-020-00384-y$$yNature News and Views article
002710810 8564_ $$81601055$$s1988573$$uhttp://cds.cern.ch/record/2710810/files/s41586-020-2006-5.pdf$$yFulltext
002710810 960__ $$a13
002710810 980__ $$aARTICLE
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