Title: Precision determination of the strong coupling constant within a global PDF analysis Show Chinese title

Title: 强耦合常数的精确确定在全球PDF分析中

Abstract: We present a determination of the strong coupling constant $\alpha_s(m_Z)$ based on the NNPDF3.1 determination of parton distributions, which for the first time includes constraints from jet production, top-quark pair differential distributions, and the $Z$ $p_T$ distributions using exact NNLO theory. Our result is based on a novel extension of the NNPDF methodology - the correlated replica method - which allows for a simultaneous determination of $\alpha_s$ and the PDFs with all correlations between them fully taken into account. We study in detail all relevant sources of experimental, methodological and theoretical uncertainty. At NNLO we find $\alpha_s(m_Z) = 0.1185 \pm 0.0005^\text{(exp)}\pm 0.0001^\text{(meth)}$, showing that methodological uncertainties are negligible. We conservatively estimate the theoretical uncertainty due to missing higher order QCD corrections (N$^3$LO and beyond) from half the shift between the NLO and NNLO $\alpha_s$ values, finding $\Delta\alpha^{\rm th}_s =0.0011$. Show Chinese abstract

Abstract: 我们基于部分子分布的NNPDF3.1确定，提出了对强耦合常数$\alpha_s(m_Z)$的确定，这是首次包括来自喷注产生、顶夸克对微分分布以及使用精确的NNLO理论的$Z$ $p_T$ 分布的约束。 我们的结果基于NNPDF方法的新扩展——相关副本方法——该方法允许同时确定$\alpha_s$和PDF，并充分考虑它们之间的所有相关性。 我们详细研究了所有相关的实验、方法和理论不确定性。 在NNLO下，我们发现$\alpha_s(m_Z) = 0.1185 \pm 0.0005^\text{(exp)}\pm 0.0001^\text{(meth)}$，表明方法学上的不确定性可以忽略不计。 我们保守地估计由于缺失高阶QCD修正（N$^3$LO及更高阶）带来的理论不确定性，方法是取NLO和NNLO$\alpha_s$值之间变化的一半，得出$\Delta\alpha^{\rm th}_s =0.0011$。