CAREER: Constraining Parton Distribution Functions for New-Physics Searches

这个项目涉及原子核的基本组成部分——核子的飞尺度（比纳米尺度小一百万倍）物理学。随着实验精度的不断提高，理论需要接受更严格的检验，因此需要高度精确的理论计算来推进我们对核子结构的理解。在这种情况下，该项目将有助于核子性质的精确数值计算，以支持最先进的实验设施的实验项目，如美国的布鲁克海文和杰斐逊实验室，德国的GSI和日本的J-PARC。本研究涉及高性能计算方法的发展和在超级计算机上的大规模数值计算。本项目为学生在理论方法和数值方法上提供了良好的训练机会。本项目旨在改善格- qcd （LQCD）确定部分子分布函数（PDF）的系统不确定性，利用这些结果减少全局PDF拟合的不确定性，并利用它们提供更精确的标准模型输入，以帮助新物理搜索和指导即将到来的qcd前沿研究。在高能物理中，PDF不确定性是理论输入量（如希格斯产生横截面）的主要误差。在核物理方面，在RHIC和JLab 12-GeV进行了投资，以探索核子的海夸克和胶子结构。PI使用“大动量有效理论”方法对pdf的Bjorken-x依赖进行了第一次LQCD计算。后者有望为广义部子分布（GPDs）和横向动量分布（TMDs）等多维质子结构的研究打开新的机会之门。在奖励期结束时，PI将与全球PDF分析社区合作，整合LQCD结果，以提高LHC新物理搜索所需的精度，并为当前核实验室和未来EIC即将进行的测量做出预测。

This project concerns physics at the femtoscale (a million times smaller than the nanoscale) within nucleons, the fundamental building blocks of the atomic nuclei. As ever improving precision in experiments puts theories to more stringent tests, highly accurate theoretical calculations are required to advance our understanding of the nucleon structure. In this context, this project will contribute precise numerical calculations of nucleon properties in support of the experimental programs at state-of-the-art experimental facilities, such as the Brookhaven and Jefferson Laboratories in the United States, GSI in Germany, and J-PARC in Japan. This research involves the development of high-performance computational methods and large-scale numerical calculations on supercomputers. This project provides excellent training opportunities for students on both theoretical and numerical methods. This project aims to improve the systematic uncertainties in lattice-QCD (LQCD) determinations of the parton distribution functions (PDFs), to leverage these results to reduce uncertainties in global PDF fits, and to use them to provide more precise Standard-Model inputs to aid new-physics searches and guide upcoming QCD-frontier research. In high-energy physics, PDF uncertainty is the dominant error in the theoretical input to quantities such as the Higgs-production cross section. In nuclear physics, investment at RHIC and JLab 12-GeV has been made to explore the sea-quark and gluon structure of nucleons. The PI made the first LQCD calculation of the Bjorken-x dependence of the PDFs using the "large-momentum effective theory" method. The latter is expected to open new doors of opportunity to the study of multidimensional proton structure, such as generalized parton distributions (GPDs) and transverse-momentum distributions (TMDs). By the end of the award period, the PI will work with the global PDF analysis community to incorporate LQCD results, producing fits with the improved precision needed for new-physics searches at LHC and to make predictions for upcoming measurements at current nuclear laboratories and the future EIC.