Higgs production and decay in models with extra singlets and doublets - Precise predictions forthe LHC

在大型强子对撞机上发现希格斯粒子是粒子物理学的巨大成功。下一步，必须精确测量这种粒子的性质，并且必须研究这种新的玻色子是否是标准模型中的希格斯玻色子。这需要研究扩展模型，并将其与实验数据进行比较。一类有趣的扩展模型是那些附加希格斯单线态和双线态的模型。这些模型符合精度测试，并在解耦极限下接近标准模型，即如果额外的希格斯玻色子的质量变大，并且耦合选择适当。此外，它们允许对在大型强子对撞机中寻找的其他物理希格斯玻色子进行一致的描述。由于标准模型和这些扩展模型之间的差异可能很小，因此必须进行精确的理论预测，包括次领先顺序的修正。这些修正的计算需要这些理论在更高阶上的一致表述，特别是重整化。这个项目的目的是研究标准模型扩展与额外的希格斯单重态或双重态。特别是，我们将研究有一个额外的希格斯单线态或双线态的模型。我们将首先定义这些模型的完整重整化过程，并明确地在次领先阶上进行重整化。然后，将评估重要的希格斯产生和衰变过程，包括次一级强修正和电弱修正。最后，将结果应用到现有的蒙特卡罗程序中。生成的代码将提供给实验合作机构进行数据分析。

The discovery of a Higgs particle at the LHC was a spectacular success of particle physics. As next step the properties of this particle have to be measured precisely and it must be investigated whether the new boson is the Higgs boson of the Standard Model. This requires to study extended models and to compare them to experimental data. An interesting class of extended models are those with additional Higgs singlets and doublets. These models are in accordance with precision tests and approach the Standard Model in the decoupling limit, i.e. if the masses of the extra Higgs bosons get large and the couplings are chosen appropriately. Moreover, they allow for a consistent description of additional physical Higgs bosons which are searched for at the LHC. Since the differences between the Standard Model and these extended models might be small, precise theoretical predictions including corrections of next-to-leading order are mandatory. The calculation of these corrections requires a consistent formulation of these theories in higher orders and, in particular, a renormalization.This project aims at the investigation of Standard Model extensions with additional Higgs singlets or doublets. We will, in particular, study models with one additional Higgs singlet or doublet. We will first define the complete renormalization procedure of these models and work out the renormalization explicitly at next-to-leading order. Then, the important Higgs production and decay processes will be evaluated including next-to-leading-order strong and electroweak corrections. Finally, the results will be implemented into existing Monte Carlo programs. The resulting codes will be made available to the experimental collaborations for data analysis.