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arXiv 1408.5841hep-th
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四个回路上的共形行为与模式依赖

Conformal Behavior at Four Loops and Scheme (In)Dependence

Thomas A. Ryttov

摘要:

本文研究了具有SU(N)规范群的渐近自由类矢量费米子规范理论的β函数的红外零点,并计算了在相应的不动点处质量的反常维数。在两种不同的显式格式下,分别在二、三和四环层次上研究了Beta函数的不动点.这两个方案是改进的正则化不变量方案和最小动量减法方案。在朗道规范中进行搜索,规范参数的beta函数为零。然后,我们将我们的研究结果与早期相同的调查进行了修改后的最小减法,$\bar{\text{MS}}$,计划。发现质量的反常维数在三圈和四圈时比在两圈时小。这似乎是在所有三种不同的计划中观察到的一种通用模式。然后,我们估计的异常尺寸的值为$γ\sim 0.225-0.375$的12个基本的口味和三种颜色,$γ\sim 0.500 - 0.593$的两个伴随的口味和两种颜色,最后$γ\sim 1.12-1.70$的两个两个索引的口味和三种颜色的下限和上限设置的最小值和最大值分别在所有三个方案和三个和四个循环。我们的分析表明,前两种理论处于共形窗口,而后者属于手征破缺相。

英文摘要:

We search for infrared zeros of the beta function and evaluate the anomalous dimension of the mass at the associated fixed point for asymptotically free vector-like fermionic gauge theories with gauge group SU(N). The fixed points of the beta function are studied at the two, three and four loop level in two different explicit schemes. These are the modified regularization invariant, RI', scheme and the minimal momentum subtraction, mMOM, scheme. The search is performed in Landau gauge where the beta function of the gauge parameter vanishes. We then compare our findings to earlier identical investigations performed in the modified minimal subtraction, $\bar{\text{MS}}$, scheme. It is found that the value of the anomalous dimension of the mass is smaller at three and four loops than at two loops. This seems to be a generic pattern that is observed in all three different schemes. We then estimate the value of the anomalous dimension to be $γ\sim 0.225-0.375$ for twelve fundamental flavors and three colors, $γ\sim 0.500 - 0.593$ for two adjoint flavors and two colors and finally $γ\sim 1.12-1.70$ for two two-indexed flavors and three colors with the lower and upper bound set by the minimum and maximum value respectively over all three schemes and at three and four loops. Our analysis suggests that the former two theories lie in the conformal window while the latter belongs to the chirally broken phase.

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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