Theoretical predictions for the Lamb shift in helium are limited by unknown quantum electrodynamic effects of the order ${\alpha }^{7}m$, where $\alpha$ is the fine-structure constant and $m$ is the electron mass. We make an important step towards the complete calculation of these effects by deriving the most challenging part, which is induced by the virtual photon exchange between all three helium particles, the two electrons and the nucleus. The complete calculation of the ${\alpha }^{7}m$ effect including the radiative corrections will allow comparing of the nuclear charge radii determined from the electronic and muonic helium atoms and thus provide a stringent test of the standard model of fundamental interactions.

中文翻译：

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氦三重态态Lamb位移中的非辐射α7mQED效应

氦的Lamb位移的理论预测受到该阶未知量子电动力学效应的限制 ${\alpha }^7米$，在哪里 $\alpha$ 是精细结构常数， $米$是电子质量。我们通过得出最具挑战性的部分，朝着完全计算这些效应迈出重要的一步，这是由所有三个氦气粒子，两个电子和原子核之间的虚拟光子交换诱导的。的完整计算${\alpha }^7米$ 包括辐射校正在内的效应将允许比较由电子氦和电子氦原子确定的核电荷半径，从而为基本相互作用的标准模型提供了严格的检验。