The anomalous magnetic moment of the muon in the Standard Model

T. Aoyama, N. Asmussen, M. Benayoun, J. Bijnens, T. Blum, M. Bruno, I. Caprini, C. M. Carloni Calame, M. Cè, G. Colangelo, F. Curciarello, H. Czyż, I. Danilkin, M. Davier, C. T.H. Davies, M. Della Morte, S. I. Eidelman, A. X. El-Khadra, A. Gérardin, D. Giusti, M. Golterman, Steven Gottlieb, V. Gülpers, F. Hagelstein, M. Hayakawa, G. Herdoíza, D. W. Hertzog, A. Hoecker, M. Hoferichter, B. L. Hoid, R. J. Hudspith, F. Ignatov, T. Izubuchi, F. Jegerlehner, L. Jin, A. Keshavarzi, T. Kinoshita, B. Kubis, A. Kupich, A. Kupść, L. Laub, C. Lehner, L. Lellouch, I. Logashenko, B. Malaescu, K. Maltman, M. K. Marinković, P. Masjuan, A. S. Meyer, H. B. Meyer, T. Mibe, K. Miura, S. E. Müller, M. Nio, D. Nomura, A. Nyffeler, V. Pascalutsa, M. Passera, E. Perez del Rio, S. Peris, A. Portelli, M. Procura, C. F. Redmer, B. L. Roberts, P. Sánchez-Puertas, S. Serednyakov, B. Shwartz, S. Simula, D. Stöckinger, H. Stöckinger-Kim, P. Stoffer, T. Teubner, R. Van de Water, M. Vanderhaeghen, G. Venanzoni, G. von Hippel, H. Wittig, Z. Zhang, M. N. Achasov, A. Bashir, N. Cardoso, B. Chakraborty, E. H. Chao, J. Charles, A. Crivellin, O. Deineka, A. Denig, C. DeTar, C. A. Dominguez, A. E. Dorokhov, V. P. Druzhinin, G. Eichmann, M. Fael, C. S. Fischer, E. Gámiz, Z. Gelzer, J. R. Green, S. Guellati-Khelifa, D. Hatton, N. Hermansson-Truedsson, S. Holz, B. Hörz, M. Knecht, J. Koponen, A. S. Kronfeld, J. Laiho, S. Leupold, P. B. Mackenzie, W. J. Marciano, C. McNeile, D. Mohler, J. Monnard, E. T. Neil, A. V. Nesterenko, K. Ottnad, V. Pauk, A. E. Radzhabov, E. de Rafael, K. Raya, A. Risch, A. Rodríguez-Sánchez, P. Roig, T. San José, E. P. Solodov, R. Sugar, K. Yu Todyshev, A. Vainshtein, A. Vaquero Avilés-Casco, E. Weil, J. Wilhelm, R. Williams, A. S. Zhevlakov

We review the present status of the Standard Model calculation of the anomalous magnetic moment of the muon. This is performed in a perturbative expansion in the fine-structure constant α and is broken down into pure QED, electroweak, and hadronic contributions. The pure QED contribution is by far the largest and has been evaluated up to and including O(α5) with negligible numerical uncertainty. The electroweak contribution is suppressed by (mμ∕MW)2 and only shows up at the level of the seventh significant digit. It has been evaluated up to two loops and is known to better than one percent. Hadronic contributions are the most difficult to calculate and are responsible for almost all of the theoretical uncertainty. The leading hadronic contribution appears at O(α2) and is due to hadronic vacuum polarization, whereas at O(α3) the hadronic light-by-light scattering contribution appears. Given the low characteristic scale of this observable, these contributions have to be calculated with nonperturbative methods, in particular, dispersion relations and the lattice approach to QCD. The largest part of this review is dedicated to a detailed account of recent efforts to improve the calculation of these two contributions with either a data-driven, dispersive approach, or a first-principle, lattice-QCD approach. The final result reads aμSM=116591810(43)×10−11 and is smaller than the Brookhaven measurement by 3.7σ. The experimental uncertainty will soon be reduced by up to a factor four by the new experiment currently running at Fermilab, and also by the future J-PARC experiment. This and the prospects to further reduce the theoretical uncertainty in the near future – which are also discussed here – make this quantity one of the most promising places to look for evidence of new physics.

Particle Physics
External organisation(s)
High Energy Accelerator Research Organization (KEK), Advanced Science Institute, RIKEN, Nagoya University, University of Southampton, Université Paris VI - Pierre-et-Marie-Curie, Lund University, University of Connecticut, European Organization for Nuclear Research (CERN), Horia Hulubei Natl Inst R&D Phys & Nucl Engn IFIN, Horia Hulubei National Institute of Physics & Nuclear Engineering, Extreme Light Infrastruct Nucl Phys, Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Pavia, Johannes Gutenberg-Universität Mainz, GSI Helmholtzzentrum für Schwerionenforschung, Universität Bern, Università degli Studi di Catania, Istituto Nazionale di Fisica Nucleare (INFN), Roma, University of Silesia in Katowice, Université Paris-Saclay, University of Glasgow, University of Southern Denmark (SDU), Novosibirsk State University (NSU), Russian Academy of Sciences, University of Illinois at Urbana-Champaign, Université de Toulon, Universität Regensburg (UR), San Francisco State University, Indiana University Bloomington, University of Edinburgh, Universidad Autónoma de Madrid, University of Washington, Rheinische Friedrich-Wilhelms-Universität Bonn, Brookhaven National Laboratory, Humboldt-Universität zu Berlin, University of Manchester, Cornell University, University of Massachusetts, Amherst, Uppsala University, National Centre for Nuclear Research (NCBJ), York University, University of Adelaide, Ludwig-Maximilians-Universität München, Associação EURATOM/IST, Universitat Autònoma de Barcelona , Forschungszentrum Dresden Rossendorf (FZD), Saitama University, International University of Health and Welfare, Università degli Studi di Roma La Sapienza, Boston University, Technische Universität Dresden, The University of Liverpool, Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Perugia, Universidad Michoacana de San Nicolás de Hidalgo, Universität Zürich (UZH), Paul Scherrer Institute, University of Utah, University of Cape Town, Dubna, Karlsruher Institut für Technologie, Justus-Liebig-Universität Gießen (JLU), Universidad de Granada, Lawrence Berkeley National Laboratory, Syracuse University, Plymouth University , University of Colorado, Boulder, Nankai University, University of California, Santa Barbara, University of Minnesota, Twin Cities, Fermi National Accelerator Laboratory, University of California, San Diego, University of Cambridge, Instituto Politécnico Nacional
Physics Reports
No. of pages
Publication date
Peer reviewed
Austrian Fields of Science 2012
103034 Particle physics
ASJC Scopus subject areas
Physics and Astronomy(all)
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