A New Era for Lattice QCD: Unveiling the Mysteries of a Proton

可见宇宙中超过99%的质量存在于强子（中子和质子）中，它们是夸克和胶子的束缚态，是量子色动力学（QCD）的基本组成部分。量子cd理论是关于质子和中子结合到原子核中的强作用力的理论。QCD成功地描述了范围广泛的复杂过程，从亚核相互作用到宏观现象，如早期宇宙中的物质状态。在这种情况下，质子作为原子核的组成部分之一，是研究量子光盘动力学性质的理想实验室。这个项目将研究质子内夸克和胶子的动力学在理论上的非摄动量。从头计算将在晶格QCD （LQCD）中进行，这是一个研究质子结构的严格框架，需要在超级计算机上对QCD方程进行数值解。研究生将从事前沿的基础研究，确保他/她成为独立的研究人员。该项目还将支持向K-12学生推广科学的推广活动。该研究项目将在LQCD内使用最先进的模拟和现代技术进行计算。模拟将在夸克质量固定在其物理值的情况下进行，这是该领域的最新成就。将计算的可观测值的类别是价夸克和海夸克的标量、轴向和张量电荷，以及轴向和电磁形状因子。科学目标有两个方面：重现实验中已知的可观测值，作为形式主义的基准，这将允许对不太为人所知或难以测量的量进行预测；后者预计将影响新物理搜索。前一类的量是轴向和电磁形式因素，而后一类的量是标量和张量的相互作用，它可能标志着超出标准模型的物理。该项目的目标是高精度的结果和可量化的系统，以便这些计算的结果产生高可信度的观测预测。这个项目将有助于更好地理解质子的结构，对解释和指导实验有价值，并可能阐明核物理中长期存在的难题，如质子自旋。

More than 99% of the mass in the visible Universe resides in hadrons (neutrons and protons), which are bound states of quarks and gluons, the fundamental constituents of Quantum Chromodynamics (QCD). QCD is the theory governing the strong force responsible for the binding of protons and neutrons into atomic nuclei. QCD describes successfully a wide range of complex processes, from sub-nuclear interactions to macroscopic phenomena, such as the state of matter in the early Universe. In this context, the proton, one of components of the atomic nucleus, represents an ideal laboratory for studying the dynamical properties of QCD. This project will investigate theoretically non-perturbative quantities that encapsulate the dynamics of quarks and gluons within the proton. Ab initio calculations will be performed in Lattice QCD (LQCD), a rigorous framework for studying the proton structure that requires numerical solutions of the QCD equations on supercomputers. A graduate student will be engaged in cutting-edge fundamental research, ensuring his/her emergence as an independent researcher. The project will also support outreach activities promoting science to K-12 students.This research program will undertake calculations within LQCD using state-of-the-art simulations and modern techniques. The simulations will be performed with quark masses fixed to their physical values, the latest achievement of the field. The class of observables that will be computed are the scalar, axial and tensor charges for both valence and sea quarks, as well as the axial and electromagnetic form factors. The scientific objectives are two-fold: Reproduce observables that are well-known experimentally, as a benchmark of the formalism, which will then allow for predictions of lesser-known or difficult to measure quantities; the latter is expected to impact New Physics searches. Quantities of the former kind are the axial and electromagnetic form factors, while quantities of the latter kind are the scalar and tensor interactions that could signal Physics beyond the Standard Model. The project aims at high-precision results and quantifiable systematics, so that the outcome of these computations yield high-credibility predictions of observables. This project will result in a better understanding of the proton structure, will be valuable for the interpretation and guidance of experiments, and may shed light on long-standing puzzles in nuclear physics, such as the proton spin.