Phenomenological Study In Littlest Higgs Model With T-Parity And Left-Right Twin Hggs Model

In the past few decades, the remarkable agreement of experiments with theory testifies the validity of the Standard Model (SM) in describing the electroweak physics. However, we still have some reasons to believe that the SM can only be a low energy effective theory and there must be new physics at some higher energy scale around TeV. Among various new physics models, little higgs and twin higgs theory are important candidates. The two models can solve the hierarchy problem in the SM. The littlest Higgs model with T parity (LHT) and left-right twin Higgs model (LRTH) are the Higgs models which have attracted much attention in the past few years. They avoid fine-tuning and provide a natural candidate for cosmic dark matter. Basing on the running large hadron collider (LHC) and the planning international linear collider (ILC), we focus on the phenomenological effects of new particles in the LHT and LRTH models to some processes, which include the following aspects:We first study the contributions of the LHT model to FC top quark production processes pp→tc and pp→tV(V=γ.Z,g) at the LHC and compare cross sections of these processes in different new physics models, and discuss the potential to observe the clue of the LHT model via these FC processes. The study showed that the prediction of the LHT model on processes pp→tc and pp→tg can achieve the LHC detection level with reasonable values of the parameters. The observation of these FC processes at the LHC is certainly the clue of new physics, and further precise measurements of the cross sections can provide useful information about the free parameters in the LHT model, specially about the mirror quark masses.Next, we investigate the top-charm associated productions via e-γin the framework of the LHT model at the ILC and compared with the process e+e-(γγ)→tc. The numerical results showed that the cross sections of the processes increase sharply as the mirror quark masses increase, and in a large part of the allowed parameter space, the cross sections ofγγ→tc and e-γ→etc may reach the detectable level at the ILC. If these processes can be observed, some information about the FC couplings can be obtained in order to distinguish the LHT model from other new physics. If these FC processes are not to be observed, the upper limit on mirror quark masses can then be given. On the other hand, we also compare these productions in every new physics model. Due to the different values of the cross sections, the top-charm production also provides a good way to distinguish the LHT model from other new physics models.In addition, Higgs physics is one of the most important topics in particle physics nowa-days. Searching for the Higgs boson is the primary goal of the LHC. At the LHC, Higgs-boson production in association with Z or W bosons, qq’→Z(W)H,is the most promising discov-ery channel for a SM Higgs particle with a mass around 120GeV. In this paper, we estimate the corrections of the LRTH model to these processes, and our numerical results showed that, with reasonable values of the parameters in the LRTH model, the LRTH model can generate significantly contributions to these processes, which might approach the observable threshold of the LHC experiments. People can get the valuable parameters information of the models and distinguish the new models through these indirect physical signals.