次最小超对称模型中最轻CP-even希格斯性质研究
发布时间：2018-10-12 21:11
【摘要】：粒子物理学是一门研究物质构成及其相互作用的基础理论科学。2012年7月,“上帝粒子”Higgs玻色子的发现完善了粒子物理标准模型,是人类科学史上最重要的事件之一。标准模型在描述除了引力外的三种相互作用情况下夸克与轻子的相互作用方面取得了显著的成就。随着实验的开展,标准模型出现了一些无法解释的问题。如:标准模型不包括引力的问题、弱电破缺问题、中微子质量问题、Higgs质量问题以及力的统一问题等等。为了解决Higgs质量问题,人们引入了一种新的对称性——超对称(supersymmetry),建立了费米子和玻色子之间的对称性,对标准模型中的粒子都引入其超伙伴粒子(superpartner particles)。超对称的引入可以在任意阶上将fermions圈与boson圈的贡献抵消。近两年来,随着暗物质探测实验Fermi-LAT发现银心宇宙线超出以及在LHC发现Z事例超出的异常现象。最小超对称模型已经很难去解释这些现象,而次最小超对称模型则可以用来解释这些实验。其是最小超对称模型最简单的扩展,相比于最小超对称模型,次最小超对称模型(NMSSM),加入了一个单态场。单态场的引入使Higgs的质量在树图水平有一个极大的抬高,这样就不需要有很大的圈图修正来抬高Higgs质量。因此相比于最小超对称模型,NMSSM在解释125GeV Higgs数据方面显得更加的自然。次最小超对称模型预言存在三个CP-even Higgs粒子,两个CP-odd Higgs粒子和一对荷电Higgs粒子,Higgs粒子谱丰富,因此在未来Higgs工厂ILC上精确研究次最小超对称模型中Higgs粒子性质将尤为重要,研究为精确检验Higgs粒子性质以及次最小超对称模型提供理论指导。本文中,我们研究了自然的次最小超对称模型中最轻CP-even希格斯在ILC的产生,考虑到多方面的实验约束,并要求两个衡量精细调节的量△z和△h小于50的情况下,我们扫描次最小超对称模型的参数空间。假定次轻的CP-even希格斯作为类标准模型希格斯,在存活的参数空间中研究在未来线性对撞机(ILC)上最轻的CP-even希格斯粒子、(h1)的联合产生过程e+e-→Zh1。我们计算了ILC上质心能量为250 GeV时e+e-→Zh1过程的散射截面,并且讨论了h1的衰变模式。我们发现:e+e-→Zh1过程的散射截面最大可以达到84fb。散射截面随着h1质量的增加而变大,并且它主要是取决于h1希格斯的二重态成分。对于大多数的存活事例来说,h1主要衰变为b(?) 。但是对于某一确定范围的存活事例来看,h1→γγ过程的分支比率可以最大达到2%,这也是次最小超对称模型和最小超对称模型的不同点。
[Abstract]:Particle physics is a basic theoretical science for studying the composition of matter and its interaction. In July 2012, the discovery of the "God particle" Higgs boson perfected the standard model of particle physics, which is one of the most important events in the history of human science. The standard model has made remarkable achievements in describing the interaction between quark and lepton under three kinds of interactions except gravity. With the development of the experiment, there are some unexplainable problems in the standard model. For example, the standard model does not include the problem of gravity, the problem of weak electric break, the problem of neutrino mass, the problem of Higgs mass, the problem of unification of forces, and so on. In order to solve the problem of Higgs mass, a new symmetry, supersymmetric (supersymmetry), was introduced to establish the symmetry between fermion and boson, and the superpartner particle (superpartner particles). Was introduced to all the particles in the standard model. The introduction of supersymmetry can cancel the contribution of fermions cycle and boson cycle at any order. In the last two years, with the detection of dark matter, Fermi-LAT has discovered the anomaly phenomenon of silver cosmic ray overrun and Z event in LHC. The minimal supersymmetry model is difficult to explain these phenomena, while the sub-minimum supersymmetric model can be used to explain these experiments. It is the simplest extension of the minimal supersymmetric model. Compared with the minimal supersymmetric model, the sub-minimum supersymmetric model (NMSSM), adds a single state field. The introduction of the single state field makes the mass of Higgs raise greatly at the tree graph level, so there is no need for a large circle graph correction to elevate the Higgs mass. Therefore, NMSSM is more natural in interpreting 125GeV Higgs data than the minimum supersymmetry model. The sub-minimum supersymmetry model predicts the existence of three CP-even Higgs particles, two CP-odd Higgs particles and a pair of charged Higgs particles, and the rich spectrum of Higgs particles. Therefore, it is very important to accurately study the properties of Higgs particles in the sub-minimum supersymmetric model in the future Higgs factory ILC. The study provides theoretical guidance for the accurate examination of the properties of Higgs particles and the sub-minimum supersymmetry model. In this paper, we study the production of the lightest CP-even Higgs in the natural sub-minimum supersymmetry model in ILC, taking into account the multiple experimental constraints, and require two measurements of fine adjustment Z and h to be less than 50. We scan the parameter space of the sub-minimum supersymmetric model. Assuming that the sublight CP-even Higgs is the standard model of Higgs, the joint production process e-Zh1. of the lightest CP-even Higgs particle on the (ILC) of the future linear collider, (h 1) is studied in the surviving parameter space We have calculated the scattering cross sections of the e e Zh1 process with a centroid energy of 250 GeV on ILC and discussed the decay mode of h 1. It is found that the maximum scattering cross section of the e e Zh1 process can reach 84 fb. The scattering cross section increases with the increase of H 1 mass, and it is mainly determined by the double state composition of H 1 Higgs. For most survival cases, the main decay of H 1 is b (?). However, for a certain range of survival cases, the branch ratio of the H1 纬 process can be as high as 2. This is also the difference between the sub-minimum supersymmetric model and the minimal supersymmetric model.
【学位授予单位】：河南师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O572.2
本文编号：2267607
[Abstract]:Particle physics is a basic theoretical science for studying the composition of matter and its interaction. In July 2012, the discovery of the "God particle" Higgs boson perfected the standard model of particle physics, which is one of the most important events in the history of human science. The standard model has made remarkable achievements in describing the interaction between quark and lepton under three kinds of interactions except gravity. With the development of the experiment, there are some unexplainable problems in the standard model. For example, the standard model does not include the problem of gravity, the problem of weak electric break, the problem of neutrino mass, the problem of Higgs mass, the problem of unification of forces, and so on. In order to solve the problem of Higgs mass, a new symmetry, supersymmetric (supersymmetry), was introduced to establish the symmetry between fermion and boson, and the superpartner particle (superpartner particles). Was introduced to all the particles in the standard model. The introduction of supersymmetry can cancel the contribution of fermions cycle and boson cycle at any order. In the last two years, with the detection of dark matter, Fermi-LAT has discovered the anomaly phenomenon of silver cosmic ray overrun and Z event in LHC. The minimal supersymmetry model is difficult to explain these phenomena, while the sub-minimum supersymmetric model can be used to explain these experiments. It is the simplest extension of the minimal supersymmetric model. Compared with the minimal supersymmetric model, the sub-minimum supersymmetric model (NMSSM), adds a single state field. The introduction of the single state field makes the mass of Higgs raise greatly at the tree graph level, so there is no need for a large circle graph correction to elevate the Higgs mass. Therefore, NMSSM is more natural in interpreting 125GeV Higgs data than the minimum supersymmetry model. The sub-minimum supersymmetry model predicts the existence of three CP-even Higgs particles, two CP-odd Higgs particles and a pair of charged Higgs particles, and the rich spectrum of Higgs particles. Therefore, it is very important to accurately study the properties of Higgs particles in the sub-minimum supersymmetric model in the future Higgs factory ILC. The study provides theoretical guidance for the accurate examination of the properties of Higgs particles and the sub-minimum supersymmetry model. In this paper, we study the production of the lightest CP-even Higgs in the natural sub-minimum supersymmetry model in ILC, taking into account the multiple experimental constraints, and require two measurements of fine adjustment Z and h to be less than 50. We scan the parameter space of the sub-minimum supersymmetric model. Assuming that the sublight CP-even Higgs is the standard model of Higgs, the joint production process e-Zh1. of the lightest CP-even Higgs particle on the (ILC) of the future linear collider, (h 1) is studied in the surviving parameter space We have calculated the scattering cross sections of the e e Zh1 process with a centroid energy of 250 GeV on ILC and discussed the decay mode of h 1. It is found that the maximum scattering cross section of the e e Zh1 process can reach 84 fb. The scattering cross section increases with the increase of H 1 mass, and it is mainly determined by the double state composition of H 1 Higgs. For most survival cases, the main decay of H 1 is b (?). However, for a certain range of survival cases, the branch ratio of the H1 纬 process can be as high as 2. This is also the difference between the sub-minimum supersymmetric model and the minimal supersymmetric model.
【学位授予单位】：河南师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O572.2
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