Li Zheng-Yang, Ma Yan-Qing, Qiu Jian-Wei
School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China.
Center for High Energy physics, Peking University, Beijing 100871, China.
Phys Rev Lett. 2021 Feb 19;126(7):072001. doi: 10.1103/PhysRevLett.126.072001.
We present for the first time complete next-to-next-to-leading-order coefficient functions to match flavor nonsinglet quark correlation functions in position space, which are calculable in lattice QCD, to parton distribution functions (PDFs). Using PDFs extracted from experimental data and our calculated matching coefficients, we predict valence-quark correlation functions that can be confronted by lattice QCD calculations. The uncertainty of our predictions is greatly reduced with higher order matching coefficients. By performing Fourier transformation, we also obtain matching coefficients for corresponding quasi-PDFs and pseudo-PDFs. Our method of calculations can be readily generalized to evaluate the matching coefficients for sea-quark and gluon correlation functions, making the program to extract partonic structure of hadrons from lattice QCD calculations comparable with and complementary to that from experimental measurements.
我们首次给出了在位置空间中将味非单态夸克关联函数（可在格点量子色动力学中计算）与部分子分布函数（PDF）相匹配的完整次下一个领头阶系数函数。利用从实验数据中提取的PDF以及我们计算出的匹配系数，我们预测了可与格点量子色动力学计算相对比的价夸克关联函数。高阶匹配系数极大地降低了我们预测的不确定性。通过进行傅里叶变换，我们还获得了相应准PDF和伪PDF的匹配系数。我们的计算方法可以很容易地推广到评估海夸克和胶子关联函数的匹配系数，使得从格点量子色动力学计算中提取强子部分子结构的程序与从实验测量中提取的程序具有可比性且互为补充。
