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arXiv · 2512.04623

QED nuclear recoil effect in helium isotope shift

Krzysztof Pachucki·Vojtěch Patkóš·Vladimir A. Yerokhin
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Abstract

We present a detailed investigation of the leading-order $m\alpha^5$ QED correction with inclusion of the finite-nuclear-mass effects. Previously, this correction had been calculated within an expansion in the electron-nucleus mass ratio $m/M$ up to the first order. In this work, we derive formulas for the $m\alpha^5$ QED contribution that are valid up to the second order in $m/M$, and perform its calculation for the $^3$He$-$$^4$He isotope shift, leading to an improved determination of the nuclear charge-radius difference.

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Krzysztof Pachucki, Vojtěch Patkóš, Vladimir A. Yerokhin. 2025-12-04. QED nuclear recoil effect in helium isotope shift. https://arxiv.org/abs/2512.04623

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