We discuss the low-energy single-quantum positron annihilation with a bound electron. The angular distribution and the total cross section are considered. We obtain a simple analytical expression for the Coulomb potential and for the screened potential. It is worth noting that the obtained results for the screened potential are universal and independent of the explicit form of the atomic potential. It is shown that screening significantly increases the cross section. We also obtain the analogous results for near-threshold bound-free e+e− photoproduction.

中文翻译：

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低能量下正电子的单量子湮没


我们讨论了具有束缚电子的低能单量子正电子湮没。考虑了角度分布和总横截面。我们得到了库仑电位和筛选电位的简单解析表达式。值得注意的是，获得的筛选电位结果是通用的，并且与原子电位的显式形式无关。结果表明，屏蔽显着增加了横截面。我们还获得了近阈值无界 e+e− 光产生的类似结果。