次最小超對稱模型中最輕CP-even希格斯性質(zhì)研究
發(fā)布時間:2018-10-12 21:11
【摘要】:粒子物理學(xué)是一門研究物質(zhì)構(gòu)成及其相互作用的基礎(chǔ)理論科學(xué)。2012年7月,“上帝粒子”Higgs玻色子的發(fā)現(xiàn)完善了粒子物理標(biāo)準(zhǔn)模型,是人類科學(xué)史上最重要的事件之一。標(biāo)準(zhǔn)模型在描述除了引力外的三種相互作用情況下夸克與輕子的相互作用方面取得了顯著的成就。隨著實(shí)驗(yàn)的開展,標(biāo)準(zhǔn)模型出現(xiàn)了一些無法解釋的問題。如:標(biāo)準(zhǔn)模型不包括引力的問題、弱電破缺問題、中微子質(zhì)量問題、Higgs質(zhì)量問題以及力的統(tǒng)一問題等等。為了解決Higgs質(zhì)量問題,人們引入了一種新的對稱性——超對稱(supersymmetry),建立了費(fèi)米子和玻色子之間的對稱性,對標(biāo)準(zhǔn)模型中的粒子都引入其超伙伴粒子(superpartner particles)。超對稱的引入可以在任意階上將fermions圈與boson圈的貢獻(xiàn)抵消。近兩年來,隨著暗物質(zhì)探測實(shí)驗(yàn)Fermi-LAT發(fā)現(xiàn)銀心宇宙線超出以及在LHC發(fā)現(xiàn)Z事例超出的異,F(xiàn)象。最小超對稱模型已經(jīng)很難去解釋這些現(xiàn)象,而次最小超對稱模型則可以用來解釋這些實(shí)驗(yàn)。其是最小超對稱模型最簡單的擴(kuò)展,相比于最小超對稱模型,次最小超對稱模型(NMSSM),加入了一個單態(tài)場。單態(tài)場的引入使Higgs的質(zhì)量在樹圖水平有一個極大的抬高,這樣就不需要有很大的圈圖修正來抬高Higgs質(zhì)量。因此相比于最小超對稱模型,NMSSM在解釋125GeV Higgs數(shù)據(jù)方面顯得更加的自然。次最小超對稱模型預(yù)言存在三個CP-even Higgs粒子,兩個CP-odd Higgs粒子和一對荷電Higgs粒子,Higgs粒子譜豐富,因此在未來Higgs工廠ILC上精確研究次最小超對稱模型中Higgs粒子性質(zhì)將尤為重要,研究為精確檢驗(yàn)Higgs粒子性質(zhì)以及次最小超對稱模型提供理論指導(dǎo)。本文中,我們研究了自然的次最小超對稱模型中最輕CP-even希格斯在ILC的產(chǎn)生,考慮到多方面的實(shí)驗(yàn)約束,并要求兩個衡量精細(xì)調(diào)節(jié)的量△z和△h小于50的情況下,我們掃描次最小超對稱模型的參數(shù)空間。假定次輕的CP-even希格斯作為類標(biāo)準(zhǔn)模型希格斯,在存活的參數(shù)空間中研究在未來線性對撞機(jī)(ILC)上最輕的CP-even希格斯粒子、(h1)的聯(lián)合產(chǎn)生過程e+e-→Zh1。我們計算了ILC上質(zhì)心能量為250 GeV時e+e-→Zh1過程的散射截面,并且討論了h1的衰變模式。我們發(fā)現(xiàn):e+e-→Zh1過程的散射截面最大可以達(dá)到84fb。散射截面隨著h1質(zhì)量的增加而變大,并且它主要是取決于h1希格斯的二重態(tài)成分。對于大多數(shù)的存活事例來說,h1主要衰變?yōu)閎(?) 。但是對于某一確定范圍的存活事例來看,h1→γγ過程的分支比率可以最大達(dá)到2%,這也是次最小超對稱模型和最小超對稱模型的不同點(diǎn)。
[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 緯 process can be as high as 2. This is also the difference between the sub-minimum supersymmetric model and the minimal supersymmetric model.
【學(xué)位授予單位】:河南師范大學(xué)
【學(xué)位級別】:碩士
【學(xué)位授予年份】:2017
【分類號】:O572.2
本文編號: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 緯 process can be as high as 2. This is also the difference between the sub-minimum supersymmetric model and the minimal supersymmetric model.
【學(xué)位授予單位】:河南師范大學(xué)
【學(xué)位級別】:碩士
【學(xué)位授予年份】:2017
【分類號】:O572.2
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