Resonant positron annihilation on atomic electrons provides a powerful method to search for light new particles coupled to $e^{+}{e}^{-}$. Reliable estimates of production rates require a detailed characterization of electron momentum distributions. We describe a general method that harnesses the target material Compton profile to properly include electron velocity effects in resonant annihilation cross sections. We additionally find that high-$Z$ atoms can efficiently act as particle physics accelerators, providing a density of relativistic electrons that allows one to extend by several times the experimental mass reach.

中文翻译：

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通过原子电子共振正电子湮灭产生暗区粒子


原子电子上的共振正电子湮灭提供了一种寻找与 $e^{+}{e}^{-}$ 耦合的轻新粒子的强大方法。对生产率的可靠估计需要电子动量分布的详细表征。我们描述了一种通用方法，该方法利用目标材料康普顿分布来正确地将电子速度效应纳入共振湮灭截面中。我们还发现，高 $Z$ 原子可以有效地充当粒子物理加速器，提供一定的相对论电子密度，使人能够将实验质量达到数倍。