A first determination of parton distributions with theoretical uncertainties
A first determination of parton distributions with theoretical uncertainties
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DOI：
10.1140/epjc/s10052-019-7364-5
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发表时间：
2019-05
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通讯作者：
Rabah Abdul Khalek;R. Ball;S. Carrazza;S. Forte;T. Giani;Z. Kassabov;E. Nocera;R. L. Pearson;J. Rojo;L. Rottoli;M. Ubiali;C. Voisey;Michael Wilson
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作者：
Rabah Abdul Khalek;R. Ball;S. Carrazza;S. Forte;T. Giani;Z. Kassabov;E. Nocera;R. L. Pearson;J. Rojo;L. Rottoli;M. Ubiali;C. Voisey;Michael Wilson
表征质子结构的部分子分布函数（PDF）目前是大型强子对撞机（LHC）测量的大多数过程预测中不确定性的主要来源之一。在这里，我们提出了质子PDF的第一次提取，占丢失的高阶不确定性（MHOU）在固定阶QCD计算PDF测定中使用。我们证明，MHOU可以包括作为用于PDF拟合的协方差矩阵的贡献，然后介绍使用尺度变化计算此协方差矩阵的处方。我们验证我们的结果在下一个领先的顺序（NLO）通过比较已知的下一个顺序（NNLO）的修正。然后，我们构建了NNPDF3.1 NLO PDF集的变体，其中包括MHOU的影响，并评估了它们对所得到的PDF的中心值和不确定性的影响。
The parton distribution functions (PDFs) which characterize the structure of the proton are currently one of the dominant sources of uncertainty in the predictions for most processes measured at the Large Hadron Collider (LHC). Here we present the first extraction of the proton PDFs that accounts for the missing higher order uncertainty (MHOU) in the fixed-order QCD calculations used in PDF determinations. We demonstrate that the MHOU can be included as a contribution to the covariance matrix used for the PDF fit, and then introduce prescriptions for the computation of this covariance matrix using scale variations. We validate our results at next-to-leading order (NLO) by comparison to the known next order (NNLO) corrections. We then construct variants of the NNPDF3.1 NLO PDF set that include the effect of the MHOU, and assess their impact on the central values and uncertainties of the resulting PDFs.