Transverse Momentum Dependent Distributions from Lattice QCD

QCD描述了质子等强子的量子力学夸克-胶子结构。如果一个人想要解释，例如在大型强子对撞机（CERN）中的质子-质子碰撞，那么这种结构的知识作为背景信息是很重要的，而且因为QCD允许研究非阿贝尔局部规范理论的复杂性质的全部广度。一开始，研究主要集中在共线物理和简单概率分布上。同时，重点研究了对相位相关敏感的函数。在这些横向动量相关的部分分布函数（tmdpdf或简称tmd）中特别有趣。美国计划中的新型电子-离子对撞机（EIC）将以前所未有的细节研究这些问题。然而，实验上可获得的信息将不足以确定所有的tmd。（每一种夸克风味的核子有8种不同的tmd，每一种都是比约肯x和横向动量的函数，此外还有胶子tmd。）因此，实验信息必须辅以点阵QCD信息。我们希望继续这样做。几年前，我们率先制定了所需的技术并进行了数值研究，今天我们与该领域的领先团队合作。此外，我们计划计算风味分离夸克轨道角动量及其尺度依赖性。

QCD describes the quantum mechanical quark-gluon structure of hadrons like the proton. Knowledge of this structure is important as background information if one wants to interpret, e.g., proton-proton collisions at LHC (CERN), but also because QCD allows to study the full breadth of complex properties of non-Abelean local gauge theories. In the beginning, research focused on collinear physics and simple probability distributions. Meanwhile, research focuses on functions which are sensitive to phase correlations. Among these Transverse Momentum Dependent parton distribution functions (TMDPDFs or simply TMDs) are especially interesting. The projected new electron-ion collider (EIC) in the US will allow to study these in unprecedented detail. However, the experimentally accessable information will be insufficient to pin all TMDs down. (A nucleon has eight different TMDs for each quark flavor and each is a function of Bjorken x and transverse momentum, and in addition there are gluon TMDs.) Therefore, the experimental information must be supplemented by Lattice QCD information. This we want continue to do. A few years ago we were the first to formulate the needed techniques and perform numerical studies and today we collaborate with the leading groups in this field. In addition we plan to calculate the flavour separated quark orbital angular momentum and its scale dependence.