Fixed target Drell-Yan data and NNLO QCD fits of parton distribution functions
Fixed target Drell-Yan data and NNLO QCD fits of parton distribution functions
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固定目标 Drell-Yan 数据和部分子分布函数的 NNLO QCD 拟合
DOI：
10.1103/physrevd.74.054033
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发表时间：
2006
影响因子：
5
通讯作者：
F. Petriello
中科院分区：
文献类型：
--
作者：
S. Alekhin;K. Melnikov;F. Petriello
本文讨论了固定靶Drell-Yan数据对QCD中次-主导阶（NNLO）部分子分布函数提取的影响。当用于部分子分布拟合时，Drell-Yan（DY）数据在大的Bjorken $x$值处约束海夸克分布。我们发现，并不是所有可用的DY数据是有用的，以提高精度的部分子分布函数（PDF）从一个适合深非弹性散射（DIS）数据。特别是，在双轻子快度较大的情况下，我们发现部分子分布函数与DY数据之间存在一些不一致，但是，通过选择一个既具有代表性又与DIS数据一致的DY数据样本，我们能够进行一个组合PDF拟合，从而显著提高了非奇异夸克分布在x较大值时的精度。对DY过程的NNLO QCD修正是提高精度的关键。他们减少了理论预测的不确定性，使其与DY横截面的实验不确定性在一个广泛的范围内$x$。
We discuss the influence of fixed-target Drell-Yan data on the extraction of parton distribution functions at next-to-next-to-leading order (NNLO) in QCD. When used in a parton distribution fit, the Drell-Yan (DY) data constrain sea quark distributions at large values of Bjorken $x$. We find that not all available DY data are useful for improving the precision of parton distribution functions (PDFs) obtained from a fit to the deep inelastic scattering (DIS) data. In particular, some inconsistencies between DIS-based parton distribution functions and DY data for large values of dilepton rapidity are found. However, by selecting a sample of the DY data that is both representative and consistent with the DIS data, we are able to perform a combined PDF fit that significantly improves the precision of nonstrange quark distributions at large values of $x$. The NNLO QCD corrections to the DY process are crucial for improving the precision. They reduce the uncertainty of the theoretical prediction, making it comparable to the experimental uncertainty in DY cross-sections over a broad range of $x$.