Electromagnetic Properties and Hadronic Parity Violation in Lattice QCD

夸克是质子和中子内部紧密结合的基本粒子。质子和中子之间残留的强相互作用产生了所有的核物理，从导致聚变的最简单的核反应到大型不稳定原子核的复杂结构。本质上，原子核之于强色动力就像分子之于电磁力一样。强相互作用理论的数值求解正在取得巨大的进展。目前的计算能力和算法已经使现实计算触手可及。强作用力的定量知识最终将使核子和原子核进入实验室，用于研究基本对称性和探索粒子物理学标准模型的极限。PI的综合研究计划将结合理论物理和高性能计算的进步，帮助我们将关于核子和原子核的知识提升到目前为止最先进的水平。此外，该计划的范围为学生和博士后研究人员在核和计算科学方面提供了相当大的培训机会，这两个领域非常需要先进的技术劳动力。该项目的科学目标是直接从量子色动力学（QCD）中研究强束缚系统的电磁和宇称违反性质。利用点阵规范理论计算核子的磁矩和电磁极化率，探讨核子内电荷和磁性的分布。研究人员还将利用晶格QCD技术研究轻核和超核的电磁结构，包括降低夸克质量的挑战。弱相互作用在低能量下的表现将从QCD中进一步研究。非轻子弱相互作用的宇称违反分量引入了强子宇称违反，并探测了强子内部深处的夸克-夸克关联。由于在等张量通道中晶格QCD计算的可行性，将确定等张量宇称违反的晶格重整化，并首次解决电磁混合问题。在剩余的同位旋通道中，将寻求新的方法来进行未来的晶格计算。

Quarks are elementary particles that are strongly bound inside protons and neutrons. The residual strong interactions between protons and neutrons give rise to all of nuclear physics, from the simplest nuclear reactions responsible for fusion, to the intricate structure of large unstable nuclei. In essence, nuclei are to the strong 'chromodynamic' force what molecules are to the electromagnetic force. Tremendous progress is being made by solving the theory of strong interactions numerically. Current computing power and algorithms have put one within reach of realistic computations. Quantitative knowledge of the strong force will ultimately render nucleons and nuclei into laboratories for investigating fundamental symmetries and probing the limits of the Standard Model of particle physics. The comprehensive research program of the PI will combine advances in theoretical physics and high-performance computing to help advance our knowledge about nucleons and nuclei to the most advanced level yet. Moreover, the scope of this program affords both student and post-doctoral researchers considerable opportunities for training in nuclear and computational science, two areas in which an advanced technical workforce is much needed.The scientific goal of this project is to study electromagnetic and parity-violating properties of strongly bound systems directly from Quantum Chromodynamics (QCD). The distribution of charge and magnetism within nucleons will be explored by calculating their magnetic moments and electromagnetic polarizabilities using lattice gauge theory. Effort will also be geared toward studying the electromagnetic structure of light nuclei and hyper-nuclei using lattice QCD techniques, including the challenge of reducing the quark mass. Manifestations of the weak interaction at low energies will additionally be investigated from QCD. The parity-violating component of non-leptonic weak interactions introduces hadronic parity violation, and probes quark-quark correlations deep within hadrons. Due to feasibility of lattice QCD computations in the isotensor channel, lattice renormalization of isotensor parity violation will be determined and electromagnetic mixing will be addressed for the first time. Novel methods will be sought for future lattice calculations in the remaining isospin channels.