Global fits of Higgs properties and new physics

希格斯玻色子性质和新物理学的全局拟合

• 批准号: 272277510
• 负责人: Professor Herbert Dreiner, Ph.D.
• 金额: --
• 依托单位: Physikalisches Institut
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/272277510?language=en
• 关键词: Global; fits; Higgs; properties; new

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.

大型强子对撞机的一个主要目标是寻找和可能发现超越标准模型的新物理。一个重要的方面是根据现有的、动机良好的新物理模型对数据进行定量解释，即拟合。这些模型可以是完整的模型，例如约束最小超对称模型(CMSSM)、有效的TeVScale模型(如一般的MSSM)或简化模型，这些模型被构建为根据易于理解的物理参数来理解数据的子集。在任何时候，这些新型号都在与标准型号竞争，决定性的衡量标准是合身的质量。一个与技术和物理相关的问题是对希格斯扇区的研究，无论是在目标希格斯适配中，还是与BSM物理的其他特征相结合。LHC的结果已经对BSM物理施加了严格的限制。在超对称性中，关键的测量是希格斯质量，对胶子和夸克等强相互作用粒子的大量直接搜索极限，以及最近也只有像winos和中性粒子这样的弱相互作用粒子的直接搜索极限。希格斯耦合可以被纳入全球分析，但还不会产生决定性的影响。此外，还有间接的限制，其中超对称粒子通过量子校正进入，例如在稀有介子衰变中，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R宇称守恒的超对称性有关。包括对新粒子产生截面的限制在技术和概念上都是困难的。此外，例如，在CMSSM中，在标准模型之外只有五个新的自由参数的完整模型中，在可观测之间存在预期的强关联，例如在Muon的反常磁矩(g-2)µ和B介子分支比BR(bs-µ)[1]之间。在具有更大参数集的扩展模型中，这种相关性的影响通常会减弱。当前大型强子对撞机参数匹配的一个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关联。此外，制定适合质量的措施也很重要，即使是较大的参数模型也是如此，例如通过玩具模型。