Global fits of Higgs properties and new physics

大型强子对撞机的一个主要目标是寻找并可能发现超越标准模型的新物理。一个重要的方面是定量解释，即拟合，根据现有的，良好的新物理模型的数据。这些模型可以是完整的模型，如约束最小超对称模型（CMSSM），有效的TeVscale模型，如一般的MSSM，或者是简化模型，它们的构建是为了理解数据的一个子集，以容易理解的物理参数。在任何时候，这些新模型都在与标准模型竞争，决定性的措施是适合的质量。一个技术上和物理上相关的问题是对希格斯粒子的研究，要么是针对希格斯粒子，要么是与BSM物理的其他特征相结合。大型强子对撞机的实验结果已经对BSM物理学提出了严格的限制。在超对称中，关键的测量值是希格斯质量，对强相互作用粒子（如胶子和夸克）的无数直接搜索限制，以及最近对弱相互作用粒子（如winos和neutralinos）的直接搜索限制。希格斯耦合可以包含在全局分析中，但还没有决定性的影响。此外，还有间接约束，超对称粒子通过量子修正进入，例如在罕见的介子衰变中，以及暗物质遗迹密度和直接和间接暗物质探测极限。后者只与保持r宇称的超对称有关。限制新粒子的生产截面在技术上和概念上都是困难的。此外，例如，在CMSSM模型中，除了标准模型之外只有五个新的自由参数，可观测值之间存在强相关性，例如介子的异常磁矩（g - 2）µ和b介子分支比BR（Bs-µµ）[1]之间的相关性。在具有更大参数集的更扩展的模型中，这种相关性的影响通常会减弱。当前大型强子对撞机参数拟合的中心焦点是研究不同新物理部门之间的这种依赖于模型的相关性。此外，制定拟合质量的措施也很重要，即使是大参数模型，例如通过玩具模型。

A main objective of the LHC is the search for and the possible discovery of new physics beyond the Standard Model. An essential aspect is the quantitative interpretation, i.e. fits, of the data in terms of existing, well-motivated new physics models. These can be complete models, such as the constrained minimal supersymmetric model (CMSSM), effective TeVscale models like the general MSSM, or ¿simplified models¿, constructed to understand a subset of the data in terms of easily understandable physical parameters. At all times, these new models are competing against the Standard Model with the decisive measure being the quality of the fit. A technically and physically related problem is the study of the Higgs sector, either in a targeted Higgs fit or in combination with other signatures for BSM physics.The LHC results already place severe restrictions on BSM physics. In supersymmetry the key measurements are the Higgs mass, numerous direct search limits for strongly interacting particles like the gluinos and squarks, and more recently also only weakly interacting particles like the winos and neutralinos. The Higgs couplings can be included in a global analysis but do not yet have decisive impact. Furthermore, there are indirect constraints, where the supersymmetric particles enter through quantum corrections, for example in rare meson decays, as well as the dark matter relic density and direct and indirect dark matter detection limits. The latter are only relevant for R-parity conserving supersymmetry.The inclusion of limits on the production cross sections of new particles is technically and conceptually difficult. Furthermore, for example, in the CMSSM, a complete model with only five new free parameters beyond the Standard Model, there are expected strong correlations between observables, such as between the anomalous magnetic moment of the muon (g - 2)µ and the B-meson branching ratio BR(Bs- µµ) [1]. In more extended models with a larger set of parameters, the impact of such correlations is typically weakened. A central focus of current LHC parameter fits is the study of such model-dependent correlations between the different new physics sectors. In addition, it is also important to develop measures for the quality of fit, even for larger parameter models, for example through toy models.