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  • 學位論文

從對撞機尋找帶電荷希格斯粒子

Charged Higgs Search at Colliders

指導教授 : 何小剛

摘要


在大型強子對撞機發現希格斯玻色子之後,人們開始從各個可能的方向尋找超越標準模型的物理定律。其中一種可能性在於我們可能不只擁有一種希格斯玻色子,而是有更多的希格斯玻色子存在。在某些物理理論中,存在著帶電荷希格斯玻色子,而人們也試著從對撞機實驗中尋找它的存在。單電荷希格斯玻色子是帶電荷希格斯玻色子的例子之一,而在某些情況下這個玻色子只在tree level和規範玻色子耦合,而在其他模型中只在tree level和費米子耦合。然而,有可能這種單電荷希格斯玻色子同時和規範玻色子及費米子耦合。因此,考慮所有可能的耦合是相當重要的。在這篇論文中,我會著重探討尋找單電荷希格斯玻色子,考慮所有和標準模型粒子的耦合,並應用到包含這些耦合的模型。 本論文透過散射過程來尋找帶電荷希格斯玻色子,討論可能和所有標準模型中粒子耦合的情況。只與費米子和只與規範波色子的耦合出現在一些模型中,因此人們在實驗中也找出一些相對應的散射過程,所以那些數據也會在這裡使用。對於會和費米子與規範玻色子耦合的希格斯玻色子則會出現在pp→jjH , H →tb這個過程。透過分析,就可以對耦合常數設下限制,而這個分析可以適用於任何含有帶電荷希格斯玻色子的模型。在引入有耦合到費米子與規範玻色子的帶電荷希格斯粒子的模型之前,先探討任意希格斯多重態的動力學項,並且集中在特定的模型,GM模型及MGM模型。MGM模型含有在tree level耦合到費米子與$W^pm Z$的帶電荷希格斯玻色子,而且這種粒子是其他模型所沒有的。將這兩個模型用於分析中並討論其限制及顯著度,作為從對撞機中尋找單電荷希格斯玻色子的範例。

並列摘要


After the discovery of the Higgs boson at the Large Hadron Collider (LHC), people have been searched for physics beyond Standard model from every aspect. One possibility is that maybe we have not only one Higgs boson, but there are more Higgs bosons existing. In certain new physics scenarios, a charged Higgs boson is proposed in a variety of models, and people have been searching in collider experiments. A singly charged Higgs is a candidate of charged Higgs boson, and it couples only to gauge bosons in some models and couples only to fermions in other scenarios at tree level. It is also possible that the singly charged Higgs boson couples to both gauge boson and fermions instead. As a result, it is rather important to consider all the possible couplings that a charged Higgs boson may have. In this thesis, I would focus on the searches of charged Higgs boson, considering all its possible couplings to SM particle, and also applying to models that contains the couplings. The search of charged Higgs boson through several scattering processes will be provided first, and I will discuss possible processes that contains all the couplings to Standard Model particles. The coupling to fermions only and the coupling to gauge bosons only exist in some models, and people have already been looking for some processes relate to these couplings in the experiment, and data of those processes are provided. For charged Higgs bosons couple to both fermions and gauge bosons, it can be revealed through process pp→jjH , H →tb. The strength of the coupling constants would then be set through the analysis. This generic analysis is applicable to any model that contains charged Higgs bosons. Before showing a model wth charged Higgs bosons coupling to fermions and gauge bosons, a general discussion on the kinetic term of Higgs multiplets would be given first. Then I would go to specific models, Georgi-Machacek(GM) model and modified Georgi-Machacek (MGM) model. MGM model contains charged Higgs bosons that couple to both fermions and $W^pm Z$ at tree level, while such singly charged Higgs bosons do not exist in popular extended Higgs models. The analysis on charged Higgs boson would be applied to these two models to discuss constraints and sensitivities. The model gives an example for singly charged Higgs search at colliders.

參考文獻


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