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arXiv 0810.2333hep-ph
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QCD的红外有限有效电荷

Infrared finite effective charge of QCD

A. C. Aguilar, D. Binosi, J. Papavassiliou

摘要:

我们表明,规范不变处理的Schwinger-Dyson方程的QCD导致红外有限胶子传播,信号的动态生成的有效胶子质量,和非增强的鬼传播,在定性协议与最近的晶格数据。所采用的截断方案是基于箍缩技术和背景场方法之间的协同作用。它最强有力的特征之一是胶子自能的横截性被明显地保留了下来,这与理论的BRST对称性完全一致。然后,我们解释,在文献中的第一次,如何非微扰地构造一个重整化群不变量的传统胶子传播。这个新构造的量作为定义QCD的非微扰有效荷的自然起点,它在所有方面都构成了普适QED有效荷在非阿贝尔背景下的推广。这种强有效电荷在紫外线下表现出渐近自由,而在低能区它冻结在一个有限值,从而产生了QCD的红外固定点。一些可能的陷阱有关的提取这样一个有效的电荷从红外有限胶子传播,如那些发现的晶格,进行了简要讨论。

英文摘要:

We show that the gauge invariant treatment of the Schwinger-Dyson equations of QCD leads to an infrared finite gluon propagator, signaling the dynamical generation of an effective gluon mass, and a non-enhanced ghost propagator, in qualitative agreement with recent lattice data. The truncation scheme employed is based on the synergy between the pinch technique and the background field method. One of its most powerful features is that the transversality of the gluon self-energy is manifestly preserved, exactly as dictated by the BRST symmetry of the theory. We then explain, for the first time in the literature, how to construct non-perturbatively a renormalization group invariant quantity out of the conventional gluon propagator. This newly constructed quantity serves as the natural starting point for defining a non-perturbative effective charge for QCD, which constitutes, in all respects, the generalization in a non-Abelian context of the universal QED effective charge. This strong effective charge displays asymptotic freedom in the ultraviolet, while in the low-energy regime it freezes at a finite value, giving rise to an infrared fixed point for QCD. Some possible pitfalls related to the extraction of such an effective charge from infrared finite gluon propagators, such as those found on the lattice, are briefly discussed.

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