Systematic uncertainties in parton distribution functions from lattice QCD simulations at the physical point
Systematic uncertainties in parton distribution functions from lattice QCD simulations at the physical point
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DOI：
10.1103/physrevd.99.114504
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发表时间：
2019-06-17
影响因子：
5
通讯作者：
Steffens, Fernanda
中科院分区：
文献类型：
--
作者：
Alexandrou, Constantia;Cichy, Krzysztof;Steffens, Fernanda
本文利用准共线部分子分布方法，详细研究了核子的螺旋度相关和螺旋度无关的共线部分子分布函数。格点QCD计算采用扭曲质量费米子与轻夸克质量的物理值。我们给出了一个系统的和深入的帐户的显着特点进入准PDF的评估和它们的关系的光锥PDF。特别是，我们给出了详细的矩阵元素的计算，包括系统的不确定性，如激发态污染的各种来源的研究。此外，我们讨论了这里使用的非微扰重整化方案及其系统，截断傅立叶变换和不同的匹配处方的影响。最后，我们展示了改进的结果的PDF和讨论未来的方向，挑战和前景，从格点QCD完全量化的不确定性精确评估PDF。
We present a detailed study of the helicity-dependent and helicity-independent collinear parton distribution functions (PDFs) of the nucleon, using the quasi-PDF approach. The lattice QCD computation is performed employing twisted mass fermions with a physical value of the light quark mass. We give a systematic and in-depth account of the salient features entering in the evaluation of quasi-PDFs and their relation to the light-cone PDFs. In particular, we give details for the computation of the matrix elements, including the study of the various sources of systematic uncertainties, such as excited-states contamination. In addition, we discuss the nonperturbative renormalization scheme used here and its systematics, effects of truncating the Fourier transform and different matching prescriptions. Finally, we show improved results for the PDFs and discuss future directions, challenges and prospects for evaluating precisely PDFs from lattice QCD with fully quantified uncertainties.