Charged Higgs Search at Colliders

• Main Authors: Jhih-Ying Su, 蘇致穎
• Other Authors: 何小剛
• Format: Others
• Language: en_US
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/82t57u

碩士 === 國立臺灣大學 === 物理學研究所 === 107 === 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.