Theoretical investigations in preparation and for the next generation of measurements of the magnetic moment of the muon

μ子的反常磁矩（g-2）是基本粒子物理学中计算和测量最精确的量之一。未来，更精确的测量将在分析和解释标准模型之外的物理学方面发挥重要的补充作用，这可能会在大型强子对撞机上发现。在早期DFG项目的过程中，首席研究员为美国费米实验室的新（g-2）实验的成功建议做出了贡献，在德国，他是新（g-2）合作的唯一成员，特别负责解释标准模型之外的物理结果。因此，该项目的首要目标是准备对未来可能的（g-2）测量的解释。为此，将开展一项广泛的研究方案。首先，重要模型（标准模型及其超对称扩展）的预测精度将通过多循环精确计算来提高，并应用已开发的专业知识和基础设施。其次，我们将计算（g-2）的预测，并在标准模型之外的许多物理学替代方案中进行比较。重点将不仅是标准的超对称性，这已经得到了全面的研究。相反，研究较少，但动机很好，在超对称性的性质不同的情况下，兰德尔-Sundrum模型与额外的时空维度将被调查。其目的是确定哪些模型允许显着的贡献（g-2）在LHC的数据。第三，我们将研究对（g-2）没有显著贡献的模型。对于这些，我们将找到最大可能的贡献或身份条件下，显着的贡献是可能的。最后，我们将研究两个有助于改进标准模型预测的主题。一方面，将计算对所谓的强子逐光修正的贡献。另一方面，最近越来越多地讨论的问题将被考虑：通常假设的理论和实验之间的关系是正确的？应使用量子场论的见解和方法检查并可能校正相应的方程，并量化比较理论-实验的影响。

The anomalous magnetic moment (g-2) of the muon is one of the most precisely calculated and measured quantities in elementary particle physics. Future, even more precise measurements will play an important, complementary role in analysing and interpreting physics beyond the Standard Model, which may be discovered at the Large Hadron Collider. In the course of an earlier DFG project, the Principal Investigator has contributed to the successful proposal for a new (g-2) experiment at Fermilab/USA, and in Germany he is the only member of the new (g-2) collaboration and reponsible particularly for the interpretation of the results in terms of physics beyond the Standard Model. Hence, the overarching goal of the project is to prepare this interpretation of possible future (g-2) measurements. For this purpose a broad research programme will be pursued. First, the precition of the prediction in important models (the Standard Model and its supersymmetric extension) will be increased by multiloop precision calculations, applying the developed expertise and infrastructure. Second, the predictions for (g-2) will be computed and compared in many alternative scenarios for physics beyond the Standard Model. The focus will not only be on standard supersymmetry, which has been studied comprehensively already. Rather, less well studied, but well motivated, qualitatively different scenarios within supersymmetry, and the Randall-Sundrum model with extra spacetime dimensions will be investigated. The aim is to identify which models allow significant contributions to (g-2) in the light of LHC-data. Third, we will investigate models in which no significant contributions to (g-2) are known. For these we will find the largest possible contributions or identity conditions under which significant contributions are possible. Finally, we will investigate two topics which contribute to a refinement of the Standard Model prediction. On the one hand, a contribution to the so-called hadronic light-by-light corrections will be computed. On the other hand, a recently increasingly discussed question will be considered: are the usually assumed relations between theory and experiment correct? The respective equations shall be checked and possibly corrected using insights and methods from quantum field theory, and the implications on the comparison theory--experiments shall be quantified.