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

人们普遍认为，某些“超越标准模式的物理”应该存在于TeV尺度之上。这些超出标准的模型(BSM)包括各种Technicolor模型和超对称模型，其中QCD-lice Technicolor模型几乎完全被LET和Tevatron上的W和Z玻色子的精确测量所排除。此外，我们还没有观察到超对称模型中所预言的超对称粒子。最近，人们提出了新的超对称模型，如轻态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Sigma模型的，因此是不可重整化的。在这项研究中，我们从手征微扰理论的角度对这些无Higgsless模型的BSM非线性Sigma模型进行了全面的分析，我们发现：1)在任何么正理论中，具有局域费米子的Higgsless模型都不受精确的电弱数据的欢迎，2)一旦我们允许费米子离域，就有可能构造出现象上可行的Higgsless模型，3)假设理想的费米子离域在电弱精度参数中的偏差最小，4)目前对这些“理想费米子离域”Higgsless模型的约束来自于三规范玻色子顶点的测量。我们还在手征微扰分析中系统地进行了二阶评估，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.