Pak Alexey, Czarnecki Andrzej
Department of Physics, University of Alberta Edmonton, AB T6G 2G7, Canada.
Phys Rev Lett. 2008 Jun 20;100(24):241807. doi: 10.1103/PhysRevLett.100.241807.
Quantum chromodynamics (QCD) effects in the semileptonic decay b-->clnu are evaluated to the second order in the coupling constant, O(alpha(s){2}), and to several orders in the expansion in quark masses, m{c}/m{b}. Corrections are calculated for the total decay rate as well as for the first two moments of the lepton energy and the hadron system energy distributions. Translated into QED and applied to the muon decay, they decrease its predicted rate by -0.43 ppm.
在半轻子衰变b→clν中，量子色动力学（QCD）效应在耦合常数O(αs²)下被评估到二阶，并在夸克质量展开m_c/m_b中到几个阶次。计算了总衰变率以及轻子能量和强子系统能量分布的前两个矩的修正。将其转换到量子电动力学（QED）并应用于μ子衰变时，它们使预测的衰变率降低了-0.43 ppm。
