Asymptotic safety and the gaugedSU(N)nonlinearσmodel
Asymptotic safety and the gaugedSU(N)nonlinearσmodel
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渐近安全性和计量 SU(N) 非线性σ模型
DOI：
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发表时间：
2010
期刊：
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通讯作者：
O. Zanusso
中科院分区：
文献类型：
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作者：
M. Fabbrichesi;R. Percacci;A. Tonero;O. Zanusso
我们研究了d维左量规SU(N)非线性{sigma}模型的前导、二阶导数项的beta函数。在d bbb20中，我们发现了规范耦合的通常的高斯紫外不动点和戈德斯通玻色子耦合的有吸引力的非高斯不动点。后者不动点的位置控制着树能级Goldstone玻色子散射振幅的手性展开、统一性和强度。对于大N，模型是弱耦合的，在所有能量上都是统一的，并且可以用最低阶的手性微扰理论很好地描述。注意结果的尺度依赖性和方案依赖性。
We study the beta functions of the leading, two-derivative terms of the left-gauged SU(N) nonlinear {sigma} model in d dimensions. In d>2, we find the usual Gaussian ultraviolet fixed point for the gauge coupling and an attractive non-Gaussian fixed point for the Goldstone boson coupling. The position of the latter fixed point controls the chiral expansion, unitarity and the strength of the tree-level Goldstone boson scattering amplitudes. For large N the model is weakly coupled, unitary at all energies and well described by the lowest order of chiral perturbation theory. Attention is paid to the gauge and scheme dependence of the results.