The PDF4LHC21 combination of global PDF fits for the LHC Run III*
The PDF4LHC21 combination of global PDF fits for the LHC Run III*
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DOI：
10.1088/1361-6471/ac7216
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发表时间：
2022-08-01
影响因子：
3.5
通讯作者：
Yuan, C-P
中科院分区：
文献类型：
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作者：
Ball, Richard D.;Butterworth, Jon;Yuan, C-P
由部分子分布函数(PDF)编码的质子的夸克和胶子结构的精确知识，对于解释目前和未来的轻子-强子和强子-强子对撞机的高能过程是至关重要的。受到CT、MSHT和NNPDF小组在PDF测定方面的最新进展的启发，我们提出了一个更新的全球PDF Fit组合：PDF4LHC21。它基于CT18、MSHT20和NNPDF3.1集合的蒙特卡罗组合，然后是Hessian压缩或其副本压缩。开展了广泛的基准研究，以查明三个全球PDF集之间差异的根源。特别是，基于几乎相同的理论设置和输入数据集的专用拟合由这三个组执行，突出了各自的拟合方法所起的作用。我们将新的PDF4LHC21组合与它的前身PDF4LHC15组合进行了比较，展示了它们良好的总体一致性，并适度减少了关键LHC过程的PDF不确定性，例如胶子聚变中的电弱规范玻色子产生和希格斯玻色子产生。我们研究了PDF4LHC21对于大型强子对撞机包含性、基准性和差异性截面的代表性选择的现象学意义。PDF4LHC21组合是通过LHAPDF库提供的，提供了一种强大、用户友好和高效的方法来估计与即将到来的大型强子对撞机第三次运行及以后的理论计算相关的PDF不确定度。
A precise knowledge of the quark and gluon structure of the proton, encoded by the parton distribution functions (PDFs), is of paramount importance for the interpretation of high-energy processes at present and future lepton-hadron and hadron-hadron colliders. Motivated by recent progress in the PDF determinations carried out by the CT, MSHT, and NNPDF groups, we present an updated combination of global PDF fits: PDF4LHC21. It is based on the Monte Carlo combination of the CT18, MSHT20, and NNPDF3.1 sets followed by either its Hessian reduction or its replica compression. Extensive benchmark studies are carried out in order to disentangle the origin of the differences between the three global PDF sets. In particular, dedicated fits based on almost identical theory settings and input datasets are performed by the three groups, highlighting the role played by the respective fitting methodologies. We compare the new PDF4LHC21 combination with its predecessor, PDF4LHC15, demonstrating their good overall consistency and a modest reduction of PDF uncertainties for key LHC processes such as electroweak gauge boson production and Higgs boson production in gluon fusion. We study the phenomenological implications of PDF4LHC21 for a representative selection of inclusive, fiducial, and differential cross sections at the LHC. The PDF4LHC21 combination is made available via the LHAPDF library and provides a robust, user-friendly, and efficient method to estimate the PDF uncertainties associated to theoretical calculations for the upcoming Run III of the LHC and beyond.