Dynamics of nou-Iinear Sigma models and their application to the little Higgs models

人们普遍认为某些“超越标准模态的物理”应该存在于TeV尺度之上。这些超标准模型（BSM）包括各种各样的Technicolor模型和超对称模型，其中qcd类Technicolor模型几乎完全被在LET和Tevatron上对W和Z玻色子的精确测量所排除。此外，我们从未观测到超对称性模型中预测的超对称性伴侣粒子。近年来，一些新的ESM模型被提出，如轻希格斯模型和解构的无希格斯模型。这些模型是基于非线性模型的，因此是不可重整的。因此，分析这些模态包括它们的辐射修正是相当困难的。在本研究中，我们从手性微扰理论的角度对这些无希格斯模型进行了全面的分析。对于无希格斯模型，我们发现：1)在任何一元理论中，具有定域费米子的希格斯模型都不受精确电弱数据的影响；2)一旦允许费米子的离域，就有可能构建在现象学上可行的无希格斯模型；3)假设“理想费米子离域”在电弱精度参数上的偏差最小；4)目前对这些“理想费米子离域”希格斯无模型的约束来自于三规范玻色子顶点的测量。我们还在手性微扰分析中进行了系统的下阶评估，包括这些模型中的辐射修正。

It is widely believed that certain "physics beyond the standard modal" should exist above the TeV scale. These beyond the-standard models(BSM)include various Technicolor models and supeisymmetric model Among them, QCD-lice Technicolor models have been ruled out almost completely by precision measurements of W and Z bosons at LET and Tevatron. Also, we have never observed SUSY partner particles as predicted in SUSY models.Recently, new type of ESM, such as the lithe Higgs models and the deconstructed Higgsless models, has been proposed. There models ale based on the non-linear sigma models, and are thus non-renormalizable. It is therefore quite difficult to analyze these modals including their radiative corrections.In this study, from a viewpoint of chiral perturbation theory, we performed a comprehensive analysis on these BSM non-linear sigma models For Higgsless models, we lurid that 1) in any unitary theory, Higgsless models with localized fermion am disfavored by precision electroweak data, 2) it is possible to construct phenomenologically viable Higgsless models once we allow the fermion delocalization, 3) assuming ideal fermion delocalization" deviations in electroweak precision parameters axe minimized, 4) the current constraint on these “ideal fermion delocalization" Higgsless models comes from the measurement of the triple gauge boson vertices We also perfumed a systematic next order evaluation in the chiral perturbation analysis including the radiative corrections in these models.