Importance of proper renormalization scale-setting for QCD testing at colliders
Importance of proper renormalization scale-setting for QCD testing at colliders
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正确的重正化标度设置对于对撞机 QCD 测试的重要性
DOI：
10.1007/s11467-015-0518-5
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发表时间：
2015-08
影响因子：
7.5
通讯作者：
Brodsky, Stanley J.
中科院分区：
文献类型：
--
作者：
Wu, Xing-Gang;Wang, Shenq-Quan;Brodsky, Stanley J.
影响微扰量子色动力学(PQCD)分析的一个主要问题是缺乏一种方法来设置QCD运行耦合重整化标度，从而获得对物理观测的最高精度的定阶预测。最大一致性原理(PMC)消除了传统重整化尺度设定过程中的模糊性，产生了与重整化方案的选择无关的预测。在pQCD系列中，QCD耦合标度和有效夸克味个数是按顺序设定的。PMC具有坚实的理论基础，满足标准的重整化群不变性条件和由重整化群导出的所有自洽条件。通过变换强力耦合常数α的自变量来消除pQCD级数中所有非共形的{βi}项，得到了每一阶的pmc标度。{βi}项是从重整化群方程中确定的，没有歧义。然后，可以得到在每个阶次和每个相空间点的运行耦合的正确行为。PMC在NC→0阿贝尔极限下降为Gell-Mann-Low方法。在这份简短的报告中，我们总结了我们最近将PMC应用于一些对撞机过程的结果，强调了这种方法的普遍性和适用性。对hadronicZdecays的讨论表明，通过应用PMC，人们可以准确地预测每一阶的总衰变宽度和单独的衰变宽度，而不会出现尺度模糊。我们还表明，如果用PMC来确定顶夸克对的前向后向不对称性，我们就可以得到一个全面的、自洽的pQCD解释。这解释了D0合作观察到的增加不变质量的“增加-减少”行为。在较低能量下，重夸克的角分布可以用来直接确定重夸克势。还讨论了大质量夸克和轻子的角分布，包括对电磁形状因子的双圈修正的费米子分量。这些结果表明，PMC的应用系统地消除了pQCD预测的一个主要理论不确定性，从而增加了对撞机对标准模型以外可能出现的新物理的敏感性。
A primary problem affecting perturbative quantum chromodynamic (pQCD) analyses is the lack of a method for setting the QCD running-coupling renormalization scale such that maximally precise fixed-order predictions for physical observables are obtained. The Principle of Maximum Conformality (PMC) eliminates the ambiguities associated with the conventional renormalization scale-setting procedure, yielding predictions that are independent of the choice of renormalization scheme. The QCD coupling scales and the effective number of quark flavors are set order-by-order in the pQCD series. The PMC has a solid theoretical foundation, satisfying the standard renormalization group invariance condition and all of the self-consistency conditions derived from the renormalization group. The PMC scales at each order are obtained by shifting the arguments of the strong force coupling constantαsto eliminate all non-conformal {βi} terms in the pQCD series. The {βi} terms are determined from renormalization group equations without ambiguity. The correct behavior of the running coupling at each order and at each phase-space point can then be obtained. The PMC reduces in theNC→ 0 Abelian limit to the Gell-Mann-Low method. In this brief report, we summarize the results of our recent application of the PMC to a number of collider processes, emphasizing the generality and applicability of this approach. A discussion of hadronicZdecays shows that, by applying the PMC, one can achieve accurate predictions for the total and separate decay widths at each order without scale ambiguities. We also show that, if one employs the PMC to determine the top-quark pair forward-backward asymmetry at the next-to-next-to-leading order level, one obtains a comprehensive, self-consistent pQCD explanation for the Tevatron measurements of the asymmetry. This accounts for the “increasing-decreasing” behavior observed by the D0 collaboration for increasingtinvariant mass. At lower energies, the angular distributions of heavy quarks can be used to obtain a direct determination of the heavy quark potential. A discussion of the angular distributions of massive quarks and leptons is also presented, including the fermionic component of the two-loop corrections to the electromagnetic form factors. These results demonstrate that the application of the PMC systematically eliminates a major theoretical uncertainty for pQCD predictions, thus increasing collider sensitivity to possible new physics beyond the Standard Model.
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DOI：
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发表时间：
2015-01
期刊：
arXiv: High Energy Physics - Phenomenology
影响因子：
--
作者：
Jian-Ming Shen;Xing-Gang Wu;Hong-Hao Ma;H. Bi;Sheng-Quan Wang
通讯作者：
Jian-Ming Shen;Xing-Gang Wu;Hong-Hao Ma;H. Bi;Sheng-Quan Wang
影响因子：
--
作者：
GELLMANN, M;LOW, FE
通讯作者：
LOW, FE
重正化群不变性和最佳 QCD 重正化尺度设置：关键问题回顾
影响因子：
18.1
作者：
Fu, Hai-Bing;Ma, Hong-Hao;Brodsky, Stanley J;Mojaza, Matin
通讯作者：
Mojaza, Matin
DOI：
10.2172/1347945
发表时间：
2013-06
期刊：
arXiv: Accelerator Physics
影响因子：
--
作者：
Ties Behnke;James E. Brau;P. Burrows;Juan Fuster;M. Peskin;M. Stanitzki;Yasuhiro Sugimoto
通讯作者：
Ties Behnke;James E. Brau;P. Burrows;Juan Fuster;M. Peskin;M. Stanitzki;Yasuhiro Sugimoto
DOI：
10.1103/physrevd.51.5924
发表时间：
1994-12
期刊：
Physical review. D, Particles and fields
影响因子：
--
作者：
M. Neubert
通讯作者：
M. Neubert