RUI: Calculation of Higher Order Corrections to Positronium Energy Levels

RUI：正电子能级高阶修正的计算

• 批准号: 2308792
• 负责人: Gregory Adkins
• 金额: $ 24万
• 依托单位: Franklin and Marshall College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2308792&HistoricalAwards=false
• 关键词: RUI; Calculation; Higher; Order; Corrections

Positronium is the bound system consisting of the electron and its antiparticle, the positron. As such, it forms an “exotic atom”, similar in many ways to traditional simple atoms such as hydrogen and helium, but different because of its unique composition and because of its tendency to annihilate, transforming into pure electromagnetic energy in the form of high-energy photons. Many properties of positronium, such as energy levels and lifetimes, are accessible to high-precision experiments. Positronium properties can also be calculated theoretically to high precision using the methods of bound-state Quantum Electrodynamics (QED) because strong and weak interaction effects are negligible. Consequently, positronium is an ideal system for testing the limits of QED bound state physics and for exploring the consequences of agreement or disagreement between theory and experiment at this high level of precision. The activities involved in calculating the positronium energy levels will be of great educational value to the undergraduate students at Franklin & Marshall College involved as collaborators in this work. The students will learn theoretical methods and techniques of calculation more advanced than those usually encountered at the undergraduate level. They will gain valuable experience by doing the research, by preparing and giving presentations describing their results, and by publishing their work as co-authors in research journals. Positronium energy levels will be calculated to high precision using the effective quantum field theory Non-Relativistic QED (NRQED). NRQED is appropriate for this work because the energies and momenta typical of atomic systems such as positronium are small compared to the electron rest energy. Divergences will be dealt with using dimensional regularization. Energy levels can be found as the positions of the poles of the electron-positron to electron-positron four-point Green's function and their values will be calculated using bound-state perturbation theory in NRQED. Recoil corrections, which are small for atoms such as hydrogen, are large in positronium and will form a major focus of this work. Calculations of recoil corrections will be performed using the "integration by parts" identities and related methods that have recently been tested for positronium at a lower order of approximation. Improved experimental results and higher precision theory will combine to give bound-state QED one of its most stringent tests to date.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

正电子是由电子及其反粒子组成的结合系统，正阳性。因此，它形成了一个“异国原子”，在许多方面与传统的简单原子（如氢和氦气）相似，但由于其独特的成分和倾向于歼灭，以高能量照片的形式转化为纯电磁能。阳性的许多特性，例如能量水平和寿命，可以进行高精度实验。也可以使用结合状态量子电动力学（QED）的方法计算出理论上的正电子性能，因为强相互作用效应可以忽略不计。因此，阳性是测试QED结合状态物理学限制并探索理论与实验之间一致性或分歧的后果的理想系统。计算正能量水平的活动对富兰克林和马歇尔学院的本科生具有巨大的教育价值，这是这项工作的合作者。与本科生通常相比，学生将学习理论方法和计算技术更先进的方法。他们将通过进行研究，准备和提供演讲来描述其结果，并在研究期刊上发表其工作，从而获得价值经验。使用有效的量子场理论非相关性QED（NRQED），将计算出阳性能量水平。 NRQED适合这项工作，因为与电子休息能相比，原子系统的典型能量和动量很小。差异将使用维度调节处理。能量水平可以找到作为电子旋值对电子峰值四点绿色功能的位置，其值将使用NRQED中的结合状态扰动理论计算。反冲校正较小的原子（如氢）的阳性很大，并且将成为这项工作的主要重点。将使用“按零件的集成”身份和相关方法进行后坐力校正的计算，这些方法最近已在较低的近似值下进行了阳性测试。改进的实验结果和更高的精度理论将结合起来，以提供迄今为止最严格的测试之一。该奖项反映了NSF的法定任务，并使用基金会的智力优点和更广泛的影响审查标准，通过评估诚实地认为通过评估。