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arXiv 1612.03331hep-ph
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强子光对μ介子g-2的贡献

Hadronic light-by-light contribution to the muon g-2

Adolfo Guevara

摘要:

在手征微扰理论的框架下,以最轻的共振多重态为动力场(R $χ$ T),计算了强子逐光(LbL)对μ子反常磁矩$a_μ$的贡献.由于J-Parc和FNAL未来的项目将减少这种可观测的不确定性,因此必须对这种强子贡献进行更准确的预测。因此,我们计算了赝标跃迁形状因子,并提出了测量$e^+e^-\toμ^+μ^-π^0$截面和双μ子不变质谱来更精确地确定其参数。然后,我们评估了π交换对$a_μ$的贡献,得到了$(6.66\pm0.21)\cdot10^{-10}$。通过比较π交换贡献和π极近似与相应的跃迁形状因子($π$ TFF),我们发现后者低估了完整的$π$ TFF(15-20)%.然后,我们得到了$η^({}'^)$ TFF,得到了$(10.47\pm0.54)\cdot10^{-10}$的最轻赝标交换的总贡献,与以前的结果一致,误差较小。

英文摘要:

We have computed the hadronic light-by-light (LbL) contribution to the muon anomalous magnetic moment $a_μ$ in the frame of Chiral Perturbation Theory with the inclusion of the lightest resonance multiplets as dynamical fields (R$χ$T). It is essential to give a more accurate prediction of this hadronic contribution due to the future projects of J-Parc and FNAL on reducing the uncertainty in this observable. We, therefore, computed the pseudoscalar transition form factor and proposed the measurement of the $e^+e^-\toμ^+μ^-π^0$ cross section and dimuon invariant mass spectrum to determine more accurately its parameters. Then, we evaluated the pion exchange contribution to $a_μ$, obtaining $(6.66\pm0.21)\cdot10^{-10}$. By comparing the pion exchange contribution and the pion-pole approximation to the corresponding transition form factor ($π$TFF) we recalled that the latter underestimates the complete $π$TFF by (15-20)\%. Then, we obtained the $η^({}'^)$ TFF, obtaining a total contribution of the lightest pseudoscalar exchanges of $(10.47\pm0.54)\cdot10^{-10}$, in agreement with previous results and with smaller error.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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