arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2008.07362hep-ph
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用最大共形性原理的单尺度方法计算达到$\mathcal{O}(α_s^4)$级QCD修正的$Z$ -玻色子强子衰变宽度

$Z$-boson hadronic decay width up to $\mathcal{O}(α_s^4)$-order QCD corrections using the single-scale approach of the principle of maximum conformality

Xu-Dong Huang, Xing-Gang Wu, Xu-Chang Zheng, Qing Yu, Sheng-Quan Wang, Jian-Ming Shen

摘要:

本文利用$\mathcal{O}(α_s^4)$阶量子色动力学(QCD)修正和最大共形性原理(PMC),研究了$Z$玻色子强子衰变宽度的性质。利用PMC单标度方法,我们得到了$Z$玻色子强子衰变宽度的精确的重整化标度与方案无关的微扰QCD(pQCD)修正,它与重整化标度的选择无关.在应用PMC之后,得到了一个更收敛的pQCD级数;并且来自未知$\mathcal{O}(α_s^5)$阶项的贡献被高度抑制,例如保守地,我们得到了$ΔΓ_{\rm Z}^{\rm had}|^{{\cal O}(α_s^5)}_{\rm PMC}\simeq \pm 0.004$ MeV。结合已知的电-弱(EW)修正、QED修正、EW-QCD混合修正和QED-QCD混合修正,我们最终预测的强子$Z$衰变宽度为$Γ_{\rm Z}^{\rm had}=1744.439^{+1.390}_{-1.433}$ MeV,与实验测量的PDG整体拟合值$1744.4\pm 2.0$ MeV一致.

英文摘要:

In the paper, we study the properties of the $Z$-boson hadronic decay width by using the $\mathcal{O}(α_s^4)$-order quantum chromodynamics (QCD) corrections with the help of the principle of maximum conformality (PMC). By using the PMC single-scale approach, we obtain an accurate renormalization scale-and-scheme independent perturbative QCD (pQCD) correction for the $Z$-boson hadronic decay width, which is independent to any choice of renormalization scale. After applying the PMC, a more convergent pQCD series has been obtained; and the contributions from the unknown $\mathcal{O}(α_s^5)$-order terms are highly suppressed, e.g. conservatively, we have $ΔΓ_{\rm Z}^{\rm had}|^{{\cal O}(α_s^5)}_{\rm PMC}\simeq \pm 0.004$ MeV. In combination with the known electro-weak (EW) corrections, QED corrections, EW-QCD mixed corrections, and QED-QCD mixed corrections, our final prediction of the hadronic $Z$ decay width is $Γ_{\rm Z}^{\rm had}=1744.439^{+1.390}_{-1.433}$ MeV, which agrees with the PDG global fit of experimental measurements, $1744.4\pm 2.0$ MeV.

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