Effect of changes of variable flavor number scheme on parton distribution functions and predicted cross sections
Effect of changes of variable flavor number scheme on parton distribution functions and predicted cross sections
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DOI：
10.1103/physrevd.86.074017
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发表时间：
2012-01
影响因子：
5
通讯作者：
R. Thorne
中科院分区：
文献类型：
--
作者：
R. Thorne
我考虑了重口味结构功能的通用质量可变风味数方案（GM-VFNS）的次领先级（NLO）和次领先级（NNLO）定义的变化。我还定义了一个新的“最佳”方案选择，以提高从一种风味数过渡到下一种风味数的平滑性。我研究了一组固定的部分分布函数（pdf）的结构函数的变化，以及当对每个GM-VFNS执行新的mstw2008类型的数据全局拟合时pdf的变化。在NLO，部分子分布，以及在强子对撞机上使用它们的预测，可以从平均值变化2-3%。在NNLO中，随着GM-VFNS定义的变化，稳定性要高得多，pdf和预测的变化小于1%，大多数变化都在非常小的x值上。因此，在考虑部分子分布时，质量方案变化是一个额外的和重要的不确定性来源，但与所有摄动不确定性一样，它随着高阶的不确定性而迅速减少。
I consider variations in the definitions, at next-to-leading order (NLO) and at next-to-next-to leading order (NNLO), of a General-Mass Variable Flavour Number Scheme (GM-VFNS) for heavy flavour structure functions. I also define a new "optimal" scheme choice improving the smoothness of the transition from one flavour number to the next. I investigate the variation of the structure function for a fixed set of parton distribution functions (PDFs) and also the change in the PDFs when a new MSTW2008-type global fit to data is performed for each GM-VFNS. At NLO the parton distributions, and predictions using them at hadron colliders, can vary by 2-3% from the mean value. At NNLO there is far more stability with varying GM-VFNS definition, and changes in PDFs and predictions are less than 1%, with most variation at very small x values. Hence, mass-scheme variation is an additional and significant source of uncertainty when considering parton distributions, but as with all perturbative uncertainties, it diminishes quickly as higher orders are included.