有效场论在强相互作用及希格斯物理中的应用

Effective field theory (EFT) nowadays is widely regarded as the powerful tool to tackle all kinds of particle physics phenomenology. It provides a modern, and model-independent theoretical framework. This project intends to employ several well-known effective field theories, such as nonrelativistic QCD, nonrelativistic QED, heavy quark effective theory, chiral perturbation theory, to systematically investigate some frontier (or fundamental) problems in the field of heavy quark physics (or possibly the realm of atomic physics). The key feature of this project is that is based on the first-principle field-theoretical approach. In contrast with the phenomenological models, this approach bears clear power counting rule and admits a systematic renormalization procedure. The major goals of this project include: Compute a series of higher-order corrections for numerous heavy quarkonium annihilation decay processes, and confront with the experimental measurements; Taking the double charmonium exclusive production at B factories as a rich theoretical laboratory, we attempt to make some progress in ultimately resolving the long-standing endpoint singularity problem in light-cone approach; Elaborate the inherent relation between NRQCD/HQET approaches and the light-cone approach for the hard exclusive reactions involving heavy hadrons, and refactorize the leading-twist light-cone distribution amplitudes of heavy-flavored mesons such as B, D mesons; Explore the potential application of the nonrelativistic gauge effective field theory to the area of atomic physics; Employs the nonrelativistic EFT technique to investigate the short-range force between Higgs boson and the other heavy particles in Standard Model.

有效场论是目前公认的粒子物理唯像学研究的有力武器。它提供了一个现代的，模型不依赖的理论框架。该项目拟利用诸多著名的有效场论如非相对论性的量子电动力学, 非相对论性的量子色动力学, 重夸克有效场论，手征微扰论等对强相互作用的重夸克能区（及原子物理领域）的一些前沿或基础问题进行深入研究。该项目的核心创新性在于它是基于第一原理的、不依赖模型的场论方法，其相对于唯像模型的优点在于有着明确的误差分析及系统的重整化手段。我们的主要研究目标是:计算诸多重夸克偶素湮灭过程中的系列高阶修正；通过B工厂上双粲偶素遍举产生作为理论实验室尝试解决端点奇异性；阐明非相对论性 QCD/重夸克有效理论方法和光锥因子化方法对涉及重味强子的硬遍举过程的内在理论联系，并对于重味介子如B介子，D介子的领头扭度的光锥分布振幅进行重因子化；寻找非相对论QE在原子物理中可能的应用；研究希格斯粒子与其它标准模型重粒子之间的短程相互作用

本项目主要基于有效场论非相对论性量子色动力学（NRQCD）的框架，研究了重夸克偶素的产生与衰变过程的高阶修正。国际上首次计算了重夸克偶素遍举产生与单举衰变过程的次次领头阶辐射修正，在国际上引起了积极反响。这些工作对NRQCD因子化在次次领头阶的成立进行了非平庸检验，并对NRQCD应用于粲夸克偶素微扰展开的收敛性提出了挑战；此外，本项目还在国际上首次计算了P波重夸克偶素衰变过程的次次领头阶修正。另外，本项目在国际上首次计算了正负电子对撞机上希格斯玻色子和Z玻色子联合产生过程的两圈电弱-QCD联合修正，为我国的CEPC提供了重要的理论参考。该项目还在1+1维QCD方面取得一系列前沿成果，在大N极限下研究了对介子结构有参照价值的规范无关的能量分解；同时，本项目也对1+1维下强子的准部分子分布函数（Partonic quasi-distributions）进行了系统研究，解析推导1+1维下了的quasi-PDF以及PDF的表达式， 并且数值计算了介子在不同动量下的quasi-PDFs的行为。该系列工作对于3+1维时空下利用格点量子色动力学数值模拟准部分子分布函数有参考价值。