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Measurement of the Positive Muon Anomalous Magnetic Moment to 127 ppb

D. P. Aguillard ³³, T. Albahri ³⁰, D. Allspach ⁷, J. Annala⁷, K. Badgley ⁷, S. Baeßler ³⁵, I. Bailey ^16,a, L. Bailey ²⁷, E. Barlas-Yucel ^28,b et al. (Muon $g - 2$ Collaboration)

E. Barlas-Yucel ^28,b, T. Barrett ⁶, E. Barzi ⁷, F. Bedeschi ¹⁰, M. Berz ¹⁷, M. Bhattacharya ⁷, H. P. Binney ³⁶, P. Bloom ¹⁸, J. Bono ⁷, E. Bottalico ³⁰, T. Bowcock ³⁰, S. Braun ³⁶, M. Bressler ³², G. Cantatore ^12,c, R. M. Carey ², B. C. K. Casey ⁷, D. Cauz ^26,d, R. Chakraborty ²⁹, A. Chapelain ⁶, S. Chappa⁷, S. Charity ³⁰, C. Chen ^22,21,e, M. Cheng ²⁸, R. Chislett ²⁷, Z. Chu ^21,e, T. E. Chupp ³³, C. Claessens ³⁶, F. Confortini ^9,f, M. E. Convery ⁷, S. Corrodi ¹, L. Cotrozzi ³⁰, J. D. Crnkovic ⁷, S. Dabagov ^8,g, P. T. Debevec ²⁸, S. Di Falco ¹⁰, G. Di Sciascio ¹¹, S. Donati ^10,h, B. Drendel ⁷, A. Driutti ^10,29, M. Eads ¹⁹, A. Edmonds ^2,37, J. Esquivel ⁷, M. Farooq ³³, R. Fatemi ²⁹, K. Ferraby ³⁰, C. Ferrari ^10,i, M. Fertl ¹⁴, A. T. Fienberg ³⁶, A. Fioretti ^10,i, D. Flay ³², S. B. Foster ^29,2, H. Friedsam⁷, N. S. Froemming¹⁹, C. Gabbanini ^10,i, I. Gaines ⁷, S. Ganguly ⁷, J. George ^32,j, L. K. Gibbons ⁶, A. Gioiosa ^25,k, K. L. Giovanetti ¹³, P. Girotti ^10,l, W. Gohn ²⁹, L. Goodenough ⁷, T. Gorringe ²⁹, J. Grange ³³, S. Grant ^1,27, F. Gray ²⁰, S. Haciomeroglu ^5,m, T. Halewood-Leagas ³⁰, D. Hampai ⁸, F. Han ²⁹, J. Hempstead ³⁶, D. W. Hertzog ³⁶, G. Hesketh ²⁷, E. Hess ¹⁰, A. Hibbert ³⁰, Z. Hodge ³⁶, S. Y. Hoh ^22,21,e, K. W. Hong ³⁵, R. Hong ^1,29, T. Hu ^22,21,e, Y. Hu ^21,e, M. Iacovacci ^9,f, M. Incagli ¹⁰, S. Israel ^2,32, P. Kammel ³⁶, M. Kargiantoulakis ⁷, M. Karuza ^12,n, J. Kaspar³⁶, D. Kawall ³², L. Kelton ^29,23, A. Keshavarzi ³¹, D. S. Kessler ³², K. S. Khaw ^22,21,e, Z. Khechadoorian ⁶, B. Kiburg ⁷, M. Kiburg ^7,18, O. Kim ³⁴, N. Kinnaird ², E. Kraegeloh ³³, K. R. Labe ⁶, J. LaBounty ³⁶, M. Lancaster ³¹, S. Lee ⁵, B. Li ^21,o, D. Li ^21,p, L. Li ^21,e, I. Logashenko ^4,q, A. Lorente Campos ²⁹, Z. Lu ^21,e, A. Lucà ⁷, G. Lukicov ²⁷, A. Lusiani ^10,r, A. L. Lyon ⁷, B. MacCoy ³⁶, R. Madrak ⁷, K. Makino ¹⁷, S. Mastroianni ⁹, R. McCarthy ^2,s, J. P. Miller ², S. Miozzi ¹¹, B. Mitra ³⁴, J. P. Morgan ⁷, W. M. Morse ³, J. Mott ⁷, A. Nath ^9,f, J. K. Ng ^22,21,e, H. Nguyen ⁷, Y. Oksuzian ¹, Z. Omarov ^15,5, W. Osar ⁶, R. Osofsky ³⁶, S. Park ⁵, G. Pauletta ^26,*,d, J. Peck ²⁹, G. M. Piacentino ^25,k, R. N. Pilato ³⁰, K. T. Pitts ^28,b, B. Plaster ²⁹, D. Počanić ³⁵, N. Pohlman ¹⁹, C. C. Polly ⁷, J. Price ³⁰, B. Quinn ³⁴, M. U. H. Qureshi ¹⁴, G. Rakness ⁷, S. Ramachandran ^1,j, E. Ramberg⁷, R. Reimann ¹⁴, B. L. Roberts ², D. L. Rubin ⁶, M. Sakurai ²⁷, L. Santi ^26,*,d, C. Schlesier ^28,t, A. Schreckenberger ⁷, Y. K. Semertzidis ^5,15, A. K. Soha ⁷, M. Sorbara ^11,u, J. Stapleton ⁷, D. Still⁷, D. Stöckinger ²⁴, C. Stoughton ⁷, D. Stratakis ⁷, H. E. Swanson ³⁶, G. Sweetmore ³¹, D. A. Sweigart ⁶, M. J. Syphers ¹⁹, Y. Takeuchi ^22,21,e, D. A. Tarazona ⁶, T. Teubner ³⁰, A. E. Tewsley-Booth ^29,33, V. Tishchenko ³, N. H. Tran ^2,v, W. Turner ³⁰, E. Valetov ¹⁷, D. Vasilkova ³⁰, G. Venanzoni ^30,w, T. Walton ⁷, A. Weisskopf ¹⁷, L. Welty-Rieger⁷, P. Winter ¹, Y. Wu ¹, B. Yu ³⁴, M. Yucel ⁷, E. Zaid ³⁰, Y. Zeng ^22,21,e, and C. Zhang ³⁰ (Muon $g - 2$ Collaboration)

¹Argonne National Laboratory, Lemont, Illinois, USA
²Boston University, Boston, Massachusetts, USA
³Brookhaven National Laboratory, Upton, New York, USA
⁴Budker Institute of Nuclear Physics, Novosibirsk, Russia
⁵Center for Axion and Precision Physics (CAPP)/Institute for Basic Science (IBS), Daejeon, Republic of Korea
⁶Cornell University, Ithaca, New York, USA
⁷Fermi National Accelerator Laboratory, Batavia, Illinois, USA
⁸INFN, Laboratori Nazionali di Frascati, Frascati, Italy
⁹INFN, Sezione di Napoli, Naples, Italy
¹⁰INFN, Sezione di Pisa, Pisa, Italy
¹¹INFN, Sezione di Roma Tor Vergata, Rome, Italy
¹²INFN, Sezione di Trieste, Trieste, Italy
¹³Department of Physics and Astronomy, James Madison University, Harrisonburg, Virginia, USA
¹⁴Institute of Physics and Cluster of Excellence PRISMA+, Johannes Gutenberg University Mainz, Mainz, Germany
¹⁵Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
¹⁶Lancaster University, Lancaster, United Kingdom
¹⁷Michigan State University, East Lansing, Michigan, USA
¹⁸North Central College, Naperville, Illinois, USA
¹⁹Northern Illinois University, DeKalb, Illinois, USA
²⁰Regis University, Denver, Colorado, USA
²¹School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China
²²Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, China
²³Department of Physics and Astronomy, Trinity University, San Antonio, Texas, USA
²⁴Institut für Kern- und Teilchenphysik, Technische Universität Dresden, Dresden, Germany
²⁵Università del Molise, Campobasso, Italy
²⁶Università di Udine, Udine, Italy
²⁷Department of Physics and Astronomy, University College London, London, United Kingdom
²⁸University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
²⁹University of Kentucky, Lexington, Kentucky, USA
³⁰University of Liverpool, Liverpool, United Kingdom
³¹Department of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
³²Department of Physics, University of Massachusetts, Amherst, Massachusetts, USA
³³University of Michigan, Ann Arbor, Michigan, USA
³⁴University of Mississippi, University, Mississippi, USA
³⁵University of Virginia, Charlottesville, Virginia, USA
³⁶University of Washington, Seattle, Washington, USA
³⁷City University of New York at York College, Jamaica, New York, USA

^*Deceased.
^aAlso at The Cockcroft Institute of Accelerator Science and Technology, Daresbury, United Kingdom.
^bPresent address: Virginia Tech, Blacksburg, Virginia, USA.
^cAlso at Università di Trieste, Trieste, Italy.
^dAlso at INFN Gruppo Collegato di Udine, Sezione di Trieste, Udine, Italy.
^eAlso at State Key Laboratory of Dark Matter Physics, Shanghai, China; also at Key Laboratory for Particle Astrophysics and Cosmology (MOE); and also at Shanghai Key Laboratory for Particle Physics and Cosmology, Shanghai, China.
^fAlso at Università di Napoli, Naples, Italy.
^gAlso at Lebedev Physical Institute and NRNU MEPhI, Moscow, Russia.
^hAlso at Università di Pisa, Pisa, Italy.
ⁱAlso at Istituto Nazionale di Ottica—Consiglio Nazionale delle Ricerche, Pisa, Italy.
^jPresent address: Alliance University, Bangalore, India.
^kAlso at INFN, Sezione di Roma Tor Vergata, Rome, Italy.
^lPresent address: INFN, Laboratori Nazionali di Frascati, Frascati, Italy.
^mPresent address: Istinye University, Istanbul, Türkiye.
ⁿAlso at University of Rijeka, Rijeka, Croatia.
^oAlso at Zhejiang Lab, Hangzhou, Zhejiang, China.
^pAlso at Shenzhen Technology University, Shenzhen, Guangdong, China.
^qAlso at Novosibirsk State University, Novosibirsk, Russia.
^rAlso at Scuola Normale Superiore, Pisa, Italy.
^sAlso at Northeastern University, Boston, Massachusetts, USA.
^tPresent address: Cornell University, Ithaca, New York, USA.
^uAlso at Università di Roma Tor Vergata, Rome, Italy.
^vPresent address: Institute for Interdisciplinary Research in Science and Education (ICISE), Quy Nhon, Binh Dinh, Vietnam.
^wAlso at INFN, Sezione di Pisa, Pisa, Italy.

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Phys. Rev. Lett. 135, 101802 – Published 2 September, 2025

DOI: https://doi.org/10.1103/7clf-sm2v

Abstract

A new measurement of the magnetic anomaly $a_{μ}$ of the positive muon is presented based on data taken from 2020 to 2023 by the Muon $g - 2$ Experiment at Fermi National Accelerator Laboratory (FNAL). This dataset contains over 2.5 times the total statistics of our previous results. From the ratio of the precession frequencies for muons and protons in our storage ring magnetic field, together with precisely known ratios of fundamental constants, we determine $a_{μ} = 1 165 920 710 (162) \times 10^{- 12}$ (139 ppb) for the new datasets, and $a_{μ} = 1 165 920 705 (148) \times 10^{- 12}$ (127 ppb) when combined with our previous results. The new experimental world average, dominated by the measurements at FNAL, is $a_{μ} (\exp) = 1 165 920 715 (145) \times 10^{- 12}$ (124 ppb). The measurements at FNAL have improved the precision on the world average by over a factor of 4.

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Muon Experiment Calls It a Wrap

Published 2 September, 2025

The final results from the Muon g − 2 experiment agree with the latest predictions of the muon’s magnetic properties—letting down hopes that the particle would upset the standard model’s applecart.

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Phys. Rev. Lett. 135, 101802– Published 2 September, 2025

Vol. 135, Iss. 10 — 5 September 2025

Received 3 June 2025
Accepted 9 July 2025

DOI: https://doi.org/10.1103/7clf-sm2v

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

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Measurement of the Positive Muon Anomalous Magnetic Moment to 127 ppb

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