Bound State Theory and High Precision QED: Muonium, Positronium, Hydrogen, and Pentaquarks

物理学中一个活跃的基础研究领域是对类氢原子和外来原子的研究，在这些原子中，一个粒子（如电子）被另一个粒子（如介子）所取代。对这些系统的特性进行理论研究是本项目的主要目标。近年来，这方面的实验已经达到了前所未有的精确度，在越来越强的层面上对理论提出了挑战。为了应对这一挑战，该项目将为许多基本物理常数的高精度测定提供理论输入，如电子-介子和电子-质子质量比、质子电荷半径和里德伯常数。这里发展的新的理论认识将用于下一个基本物理常数的CODATA分析。CODATA基本常数的汇编用于每个科学课堂，以及从基础研究到消费电子产品的众多科学和工程领域。该项目还将为五夸克的性质提供理论见解，五夸克是最近由欧洲核子研究组织（CERN）的LHCb合作组织发现的五夸克的束缚态。参与这项研究的研究生和本科生将获得研究、计算机、解决问题和演讲技巧。高精度类氢束缚态量子电动力学是一个活跃的理论研究领域，受到近年来惊人的实验进展和内在的智力挑战的推动。尽管在类轻氢束缚态理论方面取得了重大进展，但仍存在一些具有挑战性的问题，并将在本研究中得到解决：1)完成了对介子子中超精细分裂的所有三环辐射-反冲修正的计算；2)完成了双光子交换非湮灭图中费米子线中双环辐射插入对正电子中超精细分裂的硬三环修正的计算；3)完成了对氢和介子子中兰姆位移的所有相关三环非反冲修正的计算。以上是原子物理学中对兰姆位移最大的未知贡献。对氢和介子的超细分裂分别计算三回非反冲修正。PI将进一步发展五夸克的氢原子解释。该项目将提供它们属性的定量描述。

An area of active fundamental research in physics is the study of the hydrogen-like atoms and exotic atoms, atoms where one particle such as an electron is replaced by another such as a muon. Theoretical research of the properties of these systems represents the main goal of this project. In recent years, experiments in this area have reached an unprecedented level of accuracy, challenging the theory at a stronger and stronger level. Responding to this challenge, this project will provide theoretical input to the determination with higher precision of many fundamental physical constants, such as the electron-muon and electron-proton mass ratios, the proton charge radius, and the Rydberg constant. The new theoretical understanding developed here will be used in the next CODATA analysis of the fundamental physical constants. CODATA compilations of the fundamental constants are used in every science classroom, as well as in numerous fields of science and engineering, from fundamental research to consumer electronics. This project will also provide theoretical insight in the properties of pentaquarks, the bound states of five quarks recently discovered by the LHCb Collaboration at the European Organization for Nuclear Research (CERN). Graduate and undergraduate students participating in this research will acquire research, computer, problem solving, and presentation skills. High precision quantum electrodynamics of hydrogen-like bound states is an active field of theoretical research motivated both by the spectacular experimental progress achieved in recent years and the intrinsic intellectual challenge. Despite significant progress in the theory of light hydrogen-like bound states, a number of challenging problems remain and will be addressed in this research: 1) Complete calculation of all three-loop radiative-recoil corrections to hyperfine splitting in muonium, 2) Complete calculation of hard three-loop corrections to hyperfine splitting in positronium due to two-loop radiative insertions in the fermion lines in two-photon exchange nonannihilation diagrams, 3) Complete calculation of all relevant three-loop nonrecoil corrections to the Lamb shift in hydrogen and muonium. The above represent the largest unknown contributions to the Lamb shift in atomic physics. Respective three-loop nonrecoil corrections to hyperfine splitting in hydrogen and muonium will be calculated also. The PI will further develop the hadrocharmomium interpretation of pentaquarks. The project will provide quantitative description of their properties.