Cridge T, Harland-Lang L A, Thorne R S
Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.
Department of Physics and Astronomy, University College London, London, WC1E 6BT UK.
Eur Phys J C Part Fields. 2024;84(10):1009. doi: 10.1140/epjc/s10052-024-13320-5. Epub 2024 Oct 7.
We present the first determination of the value of the strong coupling via a simultaneous global fit of the proton parton distribution functions (PDFs) at approximate LO (a LO) order in QCD. This makes use of the MSHT global PDF fitting framework, and in particular the recent theoretical advances t l;;mhat allow a PDF fit to now be performed at this order. The value of the strong coupling is found to be . This is in excellent agreement with the NNLO value of , indicating that good perturbative convergence has been found. The resulting uncertainties, calculated using the MSHT dynamic tolerance procedure, are somewhat larger, but more accurate, at a LO, due to the missing higher order theoretical uncertainties that are included at this order, but not at NNLO. We in addition present a detailed breakdown of the individual dataset sensitivity to the value of the strong coupling, with special focus on the impact of fitting dijet rather than inclusive jet data. This choice is found to have a non-negligible impact, but with overall good consistency found, especially at a LO.
我们展示了通过在 QCD 中近似 LO（a LO）阶对质子部分子分布函数（PDFs）进行同时全局拟合来首次确定强耦合常数的值。这利用了 MSHT 全局 PDF 拟合框架，特别是最近的理论进展，这使得现在能够在此阶进行 PDF 拟合。发现强耦合常数的值为 。这与 NNLO 值 非常吻合，表明已经找到了良好的微扰收敛性。使用 MSHT 动态容差程序计算出的结果不确定性在 a LO 时稍大，但更准确，这是由于缺少在此阶包含但在 NNLO 时不包含的高阶理论不确定性。此外，我们详细列出了各个数据集对强耦合常数的值的敏感性，特别关注拟合双喷注而非包容性喷注数据的影响。发现这一选择具有不可忽略的影响，但总体上具有良好的一致性，尤其是在 a LO 时。
