English

Determination of $\alpha_s(M_Z)$ via a high-precision effective coupling $\alpha^{g_1}_s(Q)$

High Energy Physics - Phenomenology 2025-01-28 v1

Abstract

We propose a novel method to determine the strong coupling of quantum chromodynamics (QCD) and fix its running behavior at all scales by using the Bjorken sum rules (BSR). The BSR defines an effective coupling αsg1(Q)\alpha^{g_1}_s(Q) which includes the nonperturbative high-twist corrections and perturbative QCD (pQCD) corrections to the leading-twist part. For the leading-twist part of αsg1(Q)\alpha^{g_1}_s(Q), we adopt the infinite-order scale-setting procedure of the principle of maximum conformality (PMC\rm{PMC}_\infty) to deal with its pQCD corrections, which reveals the intrinsic conformality of series and eliminates conventional renormalization scheme-and-scale ambiguities. Using the PMC\rm{PMC}_\infty approach, we not only eliminate \textit{the first kind of residual scale dependence} due to uncalculated higher-order terms, but also resolve the previous ``self-consistence problem". The holographic light-front QCD model is used for αsg1(Q)\alpha^{g_1}_s(Q) in the infrared region, which also reveals a conformal behavior at Q0Q\to 0. As a combination, we obtain a precise αsg1(Q)\alpha^{g_1}_s(Q) at all scales, which matches well with the known experimental data with pp-value 99%\sim99\%, we determine the strong coupling constant at the critical scale MZM_Z, αs(MZ)=0.1191±0.00120.0006\alpha_s(M_Z)=0.1191\pm{0.0012}\mp0.0006, where the first error comes from Δκ\Delta\kappa of LFHQCD model and the second error is from \textit{the second kind of residual scale dependence} that is negligible.

Keywords

Cite

@article{arxiv.2501.15525,
  title  = {Determination of $\alpha_s(M_Z)$ via a high-precision effective coupling $\alpha^{g_1}_s(Q)$},
  author = {Qing Yu and Xing-Gang Wu and Hua Zhou and Jian-Ming Shen},
  journal= {arXiv preprint arXiv:2501.15525},
  year   = {2025}
}

Comments

13 pages, 4 figures