Electroweak corrections at very high energies for multi-particle processes

随着2012年在大型强子对撞机（LHC）上发现希格斯玻色子，基本粒子物理学标准模型（SM）的最后一个缺失粒子已经建立。实际上，在LHC上研究的所有过程都被SM很好地描述了，到目前为止，新物理学的研究还没有产生任何结论性的结果。另一方面，需要超越SM的物理学来解释暗物质和宇宙的物质-反物质不对称性。因此，SM必须在尽可能高的能量和尽可能高的精度下进行测试。理论界正在努力为对撞机过程提供足够准确的预测。这需要考虑到从强和电弱（EW）相互作用的微扰修正。如果观测量的能量比EW规范玻色子的质量大，EW修正的重要性就会增加。因此，对于LHC的许多过程，EW校正在分布的高能尾部达到几十%，这对SM之外的物理特别敏感。软共线效应理论（SCET）提供了一个直接计算主对数修正的框架。SCET是一个成熟的工具，用于计算和恢复低能强相互作用的修正，也用于LHC的过程。几年前，SCET形式主义的散射过程中，在高能量，包括EW修正已经制定。虽然它已被应用到一些简单的过程中，它到目前为止既没有被用于多粒子的过程，也没有实现在Monte Carlo generator.The本研究建议的中心目标是建立一个工具，用于计算EW校正多粒子过程的能量是大的EW规模相比。为此，我们将实现SCET形式主义到蒙特卡罗生成器MoCaNLO。虽然可以从文献中获得一些贡献，但最复杂的一个，即高尺度匹配，必须分别为每个过程计算。我们将使用矩阵元生成器Recola 2并编制相应的模型文件来自动计算这些贡献，为了评估SCET方法对EW校正的准确性，我们将相应的结果与不同过程的完整次领先阶计算的结果进行比较。最后，我们将计算在100 TeV能量范围内的几个强子过程的图形化的EW修正。基于我们的研究结果，领先的电子战校正到国家的最先进的蒙特卡罗发电机的实施将被简化。

With the discovery of the Higgs boson at the Large Hadron Collider (LHC) in 2012, the last missing particle of the Standard Model (SM) of elementary particle physics has been established. Practically all processes studied at the LHC are well described by the SM, and thesearch for new physics did not yet yield any conclusive results so far. On the other hand, physics beyond the SM is required to explaindark matter and the matter-antimatter asymmetry of the universe. Therefore, the SM must be tested up to the highest possible energies and with highest possible precision.The theory community is working hard to provide sufficiently accurate predictions for collider processes. This requires to take into account perturbative corrections from the strong and the electroweak (EW) interaction. The importance of EW corrections grows if the energies of the observables are large compared to the masses of the EW gauge bosons. As a consequence, for many processes at the LHC, EW corrections reach several tens of per cent in high-energy tails of distributions, which are particularly sensitive to physicsbeyond the SM. At future colliders in the 100 TeV range, the EW corrections are so big that their resummation is mandatory.A framework that directly offers the resummation of leading logarithmic corrections is provided by Soft Collinear Effective Theory (SCET). SCET is an established tool to calculate and resum corrections of the strong interaction at low energies but also for processes at the LHC. Some years ago, a SCET formalism for scattering processes at high energies including EW corrections has been formulated. While it has been applied to some simple processes, it has so far neither been used for multi-particle processes nor implemented in Monte Carlo generators.The central goal of this research proposal is the establishment of a tool for the calculation of EW corrections for multi-particleprocesses at energies that are large compared to the EW scale. To this end, we will implement the SCET formalism into the Monte Carlo generator MoCaNLO. While several contributions can be taken from the literature, the most complicated one, the high-scale matching, has to be calculated for each process separately. We will use the matrix-element generator Recola2 and work out a corresponding model file to automatically calculate these contributions.In order to assess the accuracy of the SCET approach for EW corrections, we will compare corresponding results with those of complete next-to-leading-order calculations for different processes. Finally, we will calculate the resummed EW corrections for several hadronic processes in the 100-TeV energy range. Based on our results, an implementation of leading EW corrections into state-of-the-art Monte Carlo generators will be simplified.