论文标题
在动量空间减法方案下的扰动QCD预测的量规依赖性
Gauge dependence of the perturbative QCD predictions under the momentum space subtraction scheme
论文作者
论文摘要
动量空间减法（MOM）方案是扰动QCD（PQCD）理论中最常用的重新规范化方案之一。在本文中，我们详细讨论了妈妈计划下的PQCD预测的量规依赖性。通常，固定顺序PQCD预测存在重新归一化量表的歧义，该预测分配了固定阶PQCD预测的任意范围和任意误差。最大形式（PMC）的原理采用重新归一化组方程，以确定耦合常数的大小，因此决定了该过程的有效动量流动，这与重新规定量表的选择无关。因此，PMC预测中没有重新归一化量表的歧义。为了将注意力集中在MOM仪表依赖性上，我们首先应用PMC来处理PQCD系列。我们采用希格斯玻色子衰变宽度，$γ（h \ to gg）$，最多五循环QCD贡献作为示例，以说明仪表依赖性在应用PMC之前和之后的行为。发现希格斯的衰减宽度$γ（h \ to gg）$非常微弱地取决于妈妈计划的选择，这与重新归一化组的不变性一致。发现在$ \ rm {MOMGG} $方案下的$γ（H \ to Gg）$的量规依赖性小于$ \ pm1 \％$，这是所有提到的MOM计划中最小的量规依赖性。
The momentum space subtraction (MOM) scheme is one of the most frequently used renormalization schemes in perturbative QCD (pQCD) theory. In the paper, we make a detailed discussion on the gauge dependence of the pQCD prediction under the MOM scheme. Conventionally, there is renormalization scale ambiguity for the fixed-order pQCD predictions, which assigns an arbitrary range and an arbitrary error for the fixed-order pQCD prediction. The principle of maximum conformality (PMC) adopts the renormalization group equation to determine the magnitude of the coupling constant and hence determines an effective momentum flow of the process, which is independent to the choice of renormalization scale. There is thus no renormalization scale ambiguity in PMC predictions. To concentrate our attention on the MOM gauge dependence, we first apply the PMC to deal with the pQCD series. We adopt the Higgs boson decay width, $Γ(H\to gg)$, up to five-loop QCD contributions as an example to show how the gauge dependence behaves before and after applying the PMC. It is found that the Higgs decay width $Γ(H\to gg)$ depends very weakly on the choices of the MOM schemes, being consistent with the renormalization group invariance. It is found that the gauge dependence of $Γ(H\to gg)$ under the $\rm{MOMgg}$ scheme is less than $\pm1\%$, which is the smallest gauge dependence among all the mentioned MOM schemes.
