Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA.
Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, China.
Phys Rev Lett. 2018 Dec 14;121(24):242001. doi: 10.1103/PhysRevLett.121.242001.
We present the first attempt to access the x dependence of the gluon unpolarized parton-distribution function (PDF), based on lattice simulations using the large-momentum effective theory approach. The lattice calculation is carried out with pion masses of 340 and 678 MeV on a (2+1)-flavor domain-wall fermion configuration with lattice spacing a=0.111 fm, for the gluon quasi-PDF matrix element with the nucleon momentum up to 0.93 GeV. Taking the normalization from similar matrix elements in the rest frame of the nucleon and pion, our results for these matrix elements are consistent with the Fourier transform of the global fit CT14 and PDF4LHC15 NNLO of the gluon PDF, within statistical uncertainty and the systematic one up to power corrections, perturbative O(α_{s}) matching and the mixing from the quark PDFs.
我们首次尝试根据大动量有效理论方法的晶格模拟，获取胶子非极化部分子分布函数（PDF）的 x 依赖性。晶格计算是在具有晶格间距 a=0.111 fm 的（2+1）-味道的格点上进行的，对于带有核子动量高达 0.93 GeV 的胶子准 PDF 矩阵元，使用的是 340 MeV 和 678 MeV 的π介子质量。从核子和π介子的静止系中类似矩阵元的归一化出发，我们的这些矩阵元的结果与胶子 PDF 的全局拟合 CT14 和 PDF4LHC15 NNLO 的傅里叶变换，在统计不确定性和系统不确定性范围内，直到幂次修正、微扰 O(α_{s})匹配以及来自夸克 PDF 的混合，都是一致的。
