Baikov P A, Chetyrkin K G, Kühn J H
Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University 1(2), Leninskie Gory, Moscow 119991, Russian Federation.
Institut für Theoretische Teilchenphysik, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
Phys Rev Lett. 2017 Feb 24;118(8):082002. doi: 10.1103/PhysRevLett.118.082002.
We analytically compute the five-loop term in the beta function which governs the running of α_{s}-the quark-gluon coupling constant in QCD. The new term leads to a reduction of the theory uncertainty in α_{s} taken at the Z-boson scale as extracted from the τ-lepton decays as well as to new, improved by one more order of perturbation theory, predictions for the effective coupling constants of the standard model Higgs boson to gluons and for its total decay rate to the quark-antiquark pairs.
我们通过解析计算了β函数中的五圈项，该β函数控制着αₛ（量子色动力学中的夸克 - 胶子耦合常数）的跑动。这一新项使得在Z玻色子标度下，从τ轻子衰变中提取的αₛ的理论不确定性有所降低，同时也对标准模型希格斯玻色子与胶子的有效耦合常数以及其衰变为夸克 - 反夸克对的总衰变率给出了新的、在微扰论上提高了一个阶次的改进预测。
