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Order Alpha Squared Corrections to Energy Levels and Decay Rates of Positronium (Physics)

对正电子能级和衰变率的阿尔法平方修正（物理）

基本信息

批准号：
8704324
负责人：
Gregory Adkins
金额：
$ 8.56万
依托单位：
Franklin and Marshall College
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
1987
资助国家：
美国
起止时间：
1987-07-15 至 1990-12-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=8704324&HistoricalAwards=false
关键词：
Order Alpha Squared Corrections Energy

项目摘要

Positronium is the positron-electron bound state. The structure of positronium is governed almost completely by QED; strong and weak corrections are small compared to electrodynamic effects. Positromium is also accessible to high precision experiments. Thus positronium is an ideal laboratory for studying QED and the bound state formalism in quantum field theory. The main quantities of physical interest in positronium are energy levels and decay rates. Several energy level splittings of n=1 and n=2 states have been measured with uncertainties on the order of a few MHz. Present theoretical evaluations of these splittings agree with experiment, with terms of order m(alpha)6 = 18.7 MHz still uncalculated. The n=1 spin-singlet and spin triplet decay rates have also been measured. The spin-triplet rate is several standard deviations away from the present theoretical value. There is an evident need to extend the theoretical calculations of energy levels and decay rates in positronium by another power of alpha. It is proposed to calculate some of these corrections and to make progress on the calculation of others. In particular it is planned to complete the calculation of n=1 and n=2 positronium energy levels through order m(alpha)6. Comparison of experiment and theory at this level will provide a detailed test of the bound state formalism and of QED.

正电子是正电子与电子结合的状态。正电子的结构几乎完全由QED控制；与电动力学效应相比，强修正和弱修正都很小。正硝酸钾也可用于高精度的实验。因此，正电子是研究量子电动力学和量子场论中束缚态形式的理想实验室。对正电子素感兴趣的主要物理量是能级和衰减率。测量了n=1和n=2态的几个能级分裂，其不确定度在几个MHz量级。目前对这些分裂的理论估计与实验相符，仍未计算出m(α)6=18.7 MHz的阶数项。还测量了n=1自旋单重态和自旋三重态的衰减率。自旋三重态速率与目前的理论值相差几个标准差。显然有必要将正电子素的能级和衰减率的理论计算扩展到另一个阿尔法次方。建议对其中一些修正进行计算，并在计算其他修正方面取得进展。特别是，计划通过m(α)6阶来完成n=1和n=2正电子能级的计算。在这一水平上的实验和理论的比较将提供对束缚态公式和QED的详细检验。