高能对撞机上量子色动力学的应用

The early run of LHC has lead to great success, including discovery of the Higgs boson of the standard model(SM), precision measurement and test of the SM, and also the searches for various new physics beyond the SM. As entering LHC Run-2 and Run-3, the experimental precision are expected to be further improved which will result in the test of the SM and searches of new physics at a new energy and new precision frontier. Meanwhile, there are also planned large collider experiments within China, like the Circular Electron Positron Collider (CEPC) and the Super proton-proton Collider (SPPC). Especially the CEPC Higgs factory will be able to measure the couplings of the Higgs boson much more precisely. All these developments on experiments will also set high standard for theoretical prediction or calculation. In this project, we plan to study the precision theoretical predictions for several important processes at above experiments using the QCD perturbation theory. We will study in details the effects of the QCD corrections to the experimental measurements. Through collaborations with the experimentalists we expect to further improve the measurements especially by reducing systematics from theoretical predictions. The ultimate goal is to further extending our understanding on the SM and also increasing the experimental sensitivity on possible new physics.

LHC的早期运行取得了极大的成功，其验证了标准模型希格斯粒子的存在，对标准模型进行了大量的精确检验和测量，并对各种可能的超出标准模型的新物理进行了广泛的寻找。接下来LHC Run-2和Run-3的运行，实验精度将可以得到进一步提升，将可以在更高的能量和精度上来检验标准模型以及寻找新物理。同时国内也在论证新的大型高能对撞机项目，包括CEPC以及SPPC，特别是CEPC将可以更精确、全面地测量希格斯粒子的耦合。实验的迅速发展也必然要求理论预言与之相匹配。本项目计划在之前研究工作的基础上，运用量子色动力学理论的微扰方法，进一步研究对撞机实验中重要物理过程的精确理论预言，并讨论其对相应实验测量的影响。通过与实验学家们的交流与合作来改进其测量，特别是降低其中来自于理论预言的系统误差。进而有助于人们更好地理解标准模型以及寻找超出标准模型的新物理。

项目针对大型强子对撞机（LHC）以及预期由中国主导的大型正负电子对撞机（CEPC）实验，围绕部分子分布函数，顶夸克以及希格斯粒子与新物理，通过量子场论微扰计算以及全局数据分析拟合的方法，为高能对撞机，特别是LHC实验上的硬散射过程，给出高精度的量子色动力学理论预言。共计发表本基金标注学术论文17篇，促进了标准模型精确检验和新物理寻找的研究。相关成果得到了国内外同行的高度认可和评价。在项目资助下，负责人作为骨干成员提出CTEQ-TEA系列分布函数，促成解决了奇异夸克分布疑难，提出了全局拟合中机器学习应用的新方案；计算了顶夸克产生及衰变的次次领头阶QCD修正，成为相关领域的标准预言；提出了检验希格斯粒子寿命的原创性方案。