Applications of one-loop and higher order lattice QCD perturbation theory

格点QCD是描述强相互作用非微扰部分最成功的候选者。为了把从格点QCD得到的观测量与测量的对应物联系起来，需要进行重整化。量子色动力学的格点微扰理论是计算重整化因子和研究格点观测量如何依赖于格点赝象的重要工具。对于目前使用的改进的晶格作用量，我们计划计算大量的丢失的单圈量-广义部分子分布的矩，胶子算子的矩阵元素和结构函数的高阶矩。为了提高微扰结果的可预测性，我们还将使用数值随机微扰理论的新方法，并计划计算高阶的相关函数及其相应的重整化因子。算符乘积展开是研究强子结构的基本理论工具。为了处理这种膨胀中的晶格伪影，我们将计算不同费米子晶格公式的电流-电流重正因子，并计划找到所谓的威尔逊系数的微扰重整化因子。

Lattice QCD is the most successful candidate to describe the non-perturbative part of the strong interactions. Renormalization is needed to relate observables obtained from lattice QCD to the measured counterparts. Lattice perturbation theory of QCD is an essential tool to compute renormalization factors and to investigate how lattice observables depend on lattice artefacts. For the presently used improved lattice actions we plan to calculate a lot of missing one-loop quantities – moments of generalized parton distributions, matrix elements of gluon operators and higher moments of structure functions. To improve the predictability of perturbative results we additionally will use the rather new method of numerical stochastic perturbation theory and plan to compute correlation functions and their corresponding renormalization factors in higher orders. The operator product expansion is the basic theoretical tool to provide most informations for the structure of hadrons. To handle lattice artefacts in that expansion we will compute the current-current correlators for different fermion lattice formulations and plan to find the perturbative renormalization factors for the so-called Wilson coefficients.