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 non-perturbative renormalization scheme used here and its systematics, effects of truncating the Fourier transform and different matching prescriptions.
Extracting Parton Distribution Functions from Lattice QCD Calculations
部分子分布函数（Parton Distribution Function，PDF）是描述强子与其中夸克和胶子之间关系的非微扰量，我们提出从具有良好“格点截面“的格点QCD计算所产生的“数据”的QCD整体分析中提取PDF，这些“数据”基本上是单强子矩阵元，它们是格点量子色动力学可计算的和微扰QCD可因子化为PDF的.为了证明良好的“格点截面“的存在，我们以Ji [1]引入的准夸克分布为例，说明了如果它可以乘法重整化，那么它可以分解为微扰论中所有阶次的概率密度函数。我们在$α_s$中以次前导顺序计算因子分解系数。
