标准模型中若恩的异常磁矩

论文标题

标准模型中若恩的异常磁矩

The anomalous magnetic moment of the muon in the Standard Model

论文作者

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

论文摘要

我们回顾了哑光异常磁矩的标准模型计算的当前状态。这是在精细结构常数$α$中进行的扰动扩展中执行的，并将其分解为纯QED，Electroweak和Hadronic贡献。纯QED的贡献是迄今为止最大的，并且已被评估为$ \ MATHCAL {O}（α^5）$，具有可忽略的数值不确定性。电动贡献被$（m_μ/m_w）^2 $抑制，并且仅显示在第七个重要数字的水平。它已被评估多达两个循环，众所周知，它比百分之一的好。 HADRONIC贡献是最难计算的，并且几乎负责所有理论不确定性。领先的守种类贡献以$ \ MATHCAL {O}（α^2）$出现，并且是由于HADRONIC真空极化引起的，而在$ \ Mathcal {o}（α^3）$时，出现了hadronic Light-Light-Light-light-light sctivating promenting贡献。鉴于可观察到的较低特征量表，必须使用非扰动方法，特别是分散关系和QCD的晶格方法来计算这些贡献。本综述的最大部分致力于详细说明最近通过数据驱动的，分散方法或第一原则的lattice-QCD方法来改善这两个贡献的努力。最终结果读取$a_μ^\ text {sm} = 116 \，591 \，810（43）\ times 10^{ - 11} $，并且比Brookhaven测量小于3.7 $σ$。当前在费米拉布（Fermilab）以及将来的J-PARC实验的新实验以及未来的J-PARC实验的新实验中，实验不确定性很快将减少到四因素。这和进一步减少不久的理论不确定性的前景在这里也被讨论，这是寻找新物理学证据的最有希望的地方之一。

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 $\mathcal{O}(α^5)$ with negligible numerical uncertainty. The electroweak contribution is suppressed by $(m_μ/M_W)^2$ 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 $\mathcal{O}(α^2)$ and is due to hadronic vacuum polarization, whereas at $\mathcal{O}(α^3)$ 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 $a_μ^\text{SM}=116\,591\,810(43)\times 10^{-11}$ and is smaller than the Brookhaven measurement by 3.7$σ$. 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.

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