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arXiv 1504.06571hep-phhep-th
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$V$ -概型中的四圈重整化群QCD和QED $β$ -函数及其与QED和QCD中Gell-Mann-Low函数的类比

The four-loop renormalization group QCD and QED $β$-functions in the $V$-scheme and their analogy with the Gell-Mann--Low function in QED and QCD

A. L. Kataev, V. S. Molokoedov

摘要:

在$SU(N_c)$规范群的情况下,得到了${\rm{V}}$ -方案中重整化群$β$ -函数第四系数的半解析表达式.在计算过程中,我们采用了$\rm{\overline{MS}}$方案中计算的QCD静势的三圈微扰近似。获得更详细的$n_f$独立的三回路贡献的静态电位,目前获得的两个组的表达式的重要性,强调。本文比较了在Landau规范下,规范无关的${\rm{V}}$ -和$\rm{\overline{MS}}$ -格式以及最小化格式中QCD的RG $β$ -函数的四圈近似的数值结构。考虑到$N$ -型轻子的QED极限,我们发现$β^{\rm{V}}$ -函数在四阶微扰修正的水平上开始不同于Gell-Mann-Low函数$Ψ(α_{\rm{MOM}})$,接受了与$N^2$成比例的附加项.考虑到这一特点,我们建议考虑$β^{\rm{V}}$ -函数作为Gell-Man-Low函数在QCD中最有理论根据的模拟。

英文摘要:

The semi-analytical expression for the forth coefficient of the renormalization group $β$-function in the ${\rm{V}}$-scheme is obtained in the case of the $SU(N_c)$ gauge group. In the process of calculations we use the three-loop perturbative approximation for the QCD static potential, evaluated in the $\rm{\overline{MS}}$-scheme. The importance of getting more detailed expressions for the $n_f$-independent three-loop contribution to the static potential,obtained at present by two groups, is emphasised. The comparison of the numerical structure of the four-loop approximations for the RG $β$- function of QCD in the gauge-independent ${\rm{V}}$- and $\rm{\overline{MS}}$-schemes and in the minimal MOM scheme in the Landau gauge are presented. Considering the limit of QED with $N$-types of leptons we discover that the $β^{\rm{V}}$-function is starting to differ from the Gell-Mann--Low function $Ψ(α_{\rm{MOM}})$ at the level of the forth-order perturbative corrections, receiving the proportional to $N^2$ additional term. Taking this feature into account, we propose to consider the $β^{\rm{V}}$-function as the most theoretically substantiated analog of the Gell-Man--Low function in QCD.

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