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arXiv 2006.07032hep-ph
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深度非弹性散射中重味PDF演化和变味数格式的不确定性

Heavy-flavor PDF evolution and variable-flavor number scheme uncertainties in deep-inelastic scattering

S. Alekhin, J. Bluemlein, S. Moch

摘要:

从固定味数(FFN)方案中的$n_f=3$轻味出发,利用QCD中重夸克的标准退耦关系,详细讨论了粲和底的重夸克部分子分布函数的构造.我们还考虑了双质量效应。此外,还研究了变味数(VFN)方案在深度非弹性散射(DIS)中的不同实现,特别是着重于$Q^2/m_h^2$中大夸克的重新表示,即交换规范玻色子$Q^2$与重夸克质量平方$m_h^2$的虚度之比.在现有的DIS粲夸克产生数据的运动学范围内,再确认效应的影响很小,因此在FFN方案中可以很好地描述它们。最后,我们研究了与VFN方案相关的理论不确定性,主要表现在小$Q^2$。

英文摘要:

We consider a detailed account on the construction of the heavy-quark parton distribution functions for charm and bottom, starting from $n_f=3$ light flavors in the fixed-flavor number (FFN) scheme and by using the standard decoupling relations for heavy quarks in QCD. We also account for two-mass effects. Furthermore, different implementations of the variable-flavor-number (VFN) scheme in deep-inelastic scattering (DIS) are studied, with the particular focus on the resummation of large logarithms in $Q^2/m_h^2$, the ratio the virtuality of the exchanged gauge-boson $Q^2$ to the heavy-quark mass squared $m_h^2$. A little impact of resummation effects if found in the kinematic range of the existing data on the DIS charm-quark production so that they can be described very well within the FFN scheme. Finally, we study the theoretical uncertainties associated to the VFN scheme, which manifest predominantly at small $Q^2$.

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