Novel and Self-Consistency Analysis of the QCD Running Coupling α <sub>s</sub>(Q) in Both the Perturbative and Nonperturbative Domains
Qing Yu, Hua Zhou, Xu-Dong Huang, Jian-Ming Shen, Xing-Gang Wu
Abstract
The quantum chromodynamics (QCD) coupling α s is the most important parameter for achieving precise QCD predictions. By using the well measured effective coupling <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msubsup> <mml:mi>α</mml:mi> <mml:mi mathvariant="normal">s</mml:mi> <mml:mrow> <mml:msub> <mml:mi>g</mml:mi> <mml:mn>1</mml:mn> </mml:msub> </mml:mrow> </mml:msubsup> <mml:mo stretchy="false">(</mml:mo> <mml:mi>Q</mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:math> defined from the Bjorken sum rules as a basis, we suggest a novel self-consistency way to fix the α s at all scales: The QCD light-front holographic model is adopted for its infrared behavior, and the fixed-order pQCD prediction under the principle of maximum conformality (PMC) is used for its high-energy behavior. Using the PMC scheme-and-scale independent perturbative series, and by transforming it into the one under the physical V scheme, we observe that a precise α s running behavior in both the perturbative and nonperturbative domains with a smooth transition from small to large scales can be achieved.