arXiv 2106.045262021-06-08hep-thhep-ph

红外QCD的小膨胀参数窗口

A window on infrared QCD with small expansion parameters

Marcela Peláez, Urko Reinosa, Julien Serreau, Matthieu Tissier, Nicolás Wschebor

备注：: 51 pages, 29 figures
DOI：: 10.1088/1361-6633/ac36b8

摘要：

对朗道规范中QCD关联函数的格点模拟证实了两个显著的事实。首先，规范扇区中的耦合常数在所有尺度下都是有限的和适度的，这表明某种微扰描述在红外动量下应该是有效的。第二，胶子传播子在动量为零时达到一个有限的非零值，对应于胶子屏蔽质量。本文综述了近年来用微扰Curci-Ferrari模型描述Landau规范QCD长距离性质的研究。后者是朗道规范中Faddeev-Popov拉格朗日量的最简单变形，其中包括树水平的胶子屏蔽质量。到目前为止，有强有力的证据表明，这种方法成功地描述了红外QCD动力学的许多方面。特别是，几个关联函数计算在一个和两个循环的订单，并与{ \it从头计算}晶格模拟进行比较。单循环计算的典型误差为10%，而两个循环的误差则下降到几倍。我们审查这样的计算在淬火近似以及在动力学夸克的存在。在后一种情况下，自发破缺的手征对称性需要超越耦合展开，但仍然可以描述在一个受控的近似方案的小参数。我们还回顾了该方法在非零温度和化学势方面的应用。

英文摘要：

Lattice simulations of the QCD correlation functions in the Landau gauge have established two remarkable facts. First, the coupling constant in the gauge sector remains finite and moderate at all scales, suggesting that some kind of perturbative description should be valid down to infrared momenta. Second, the gluon propagator reaches a finite nonzero value at vanishing momentum, corresponding to a gluon screening mass. We review recent studies which aim at describing the long-distance properties of Landau gauge QCD by means of the perturbative Curci-Ferrari model. The latter is the simplest deformation of the Faddeev-Popov Lagrangian in the Landau gauge that includes a gluon screening mass at tree-level. There are, by now, strong evidences that this approach successfully describes many aspects of the infrared QCD dynamics. In particular, several correlation functions were computed at one- and two-loop orders and compared with {\it ab-initio} lattice simulations. The typical error is of the order of ten percent for a one-loop calculation and drops to few percents at two loops. We review such calculations in the quenched approximation as well as in the presence of dynamical quarks. In the latter case, the spontaneous breaking of the chiral symmetry requires to go beyond a coupling expansion but can still be described in a controlled approximation scheme in terms of small parameters. We also review applications of the approach to nonzero temperature and chemical potential.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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