The aim of this work is to present and discuss the Ramsauer-Townsend effect in the context of low-energy positron scattering by rare gas atoms. Opposed to what happens in electron-atom scattering, the competition between the static repulsive and polarization attractive potentials makes the phenomenon improbable in positron case. Nonetheless, we show using a semiempirical potential formulation that, while the effect is explicitly observed in the total cross sections for He and Ne, for the heavier noble gases it becomes “hidden” or implicit. We show that as the atomic polarizability increases, the suppression of s-wave goes to higher energies due to the variation of the scattering length with the polarizability. No specific signature for the effect is found in the shape of the differential cross sections but curiously, while the effect is implicit in the total cross section for Ar, it generates a minimum structure in the momentum transfer cross section. The theme is presented for non-specialist audience with emphasis in basic atomic and scattering theories along with practical results, the main objective being to boost the traditional discussions with a new view on the subject.

中文翻译：

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稀有气体原子正电子散射中隐藏的拉姆绍尔-汤森效应

这项工作的目的是在稀有气体原子的低能正电子散射背景下介绍和讨论拉姆绍尔-汤森效应。与电子 - 原子散射中发生的情况相反，静态排斥和极化吸引力之间的竞争使得这种现象在正电子情况下是不可能的。尽管如此，我们使用半经验势公式表明，虽然在 He 和 Ne 的总横截面中明确观察到了这种影响，但对于较重的惰性气体，它变得“隐藏”或隐含。我们表明，随着原子极化率的增加，由于散射长度随极化率的变化，对 s 波的抑制会达到更高的能量。在微分横截面的形状中没有发现这种效应的具体特征，但奇怪的是，虽然这种效应隐含在 Ar 的总截面中，但它在动量传递截面中产生了最小结构。该主题是为非专业观众呈现的，重点是基本的原子和散射理论以及实际结果，主要目的是用对该主题的新观点来推动传统讨论。