The prediction of stellar $(\gamma ,\alpha )$ reaction rates for heavy nuclei is based on the calculation of $(\alpha ,\gamma )$ cross sections at sub-Coulomb energies. These rates are essential for modeling the nucleosynthesis of so-called $p$ nuclei. The standard calculations in the statistical model show a dramatic sensitivity to the chosen $\alpha$-nucleus potential. The present study explains the reason for this dramatic sensitivity which results from the tail of the imaginary $\alpha$-nucleus potential in the underlying optical model calculation of the total reaction cross section. As an alternative to the optical model, a simple barrier transmission model is suggested. It is shown that this simple model in combination with a well-chosen $\alpha$-nucleus potential is able to predict total $\alpha$-induced reaction cross sections for a wide range of heavy target nuclei above $A\gtrsim 150$ with uncertainties below a factor of 2. The new predictions from the simple model do not require any adjustment of parameters to experimental reaction cross sections whereas in previous statistical model calculations all predictions remained very uncertain because the parameters of the $\alpha$-nucleus potential had to be adjusted to experimental data. The new model allows us to predict the reaction rate of the astrophysically important ${}^{176}\mathrm{W}(\alpha ,\gamma ){}^{180}\mathrm{Os}$ reaction with reduced uncertainties, leading to a significantly lower reaction rate at low temperatures. The new approach could also be validated for a broad range of target nuclei from $A\approx 60$ up to $A\gtrsim 200$.

中文翻译：

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使用新方法成功预测天文学上与天体相关的亚库仑能量下的总α诱导反应截面。

恒星的预测 $（\gamma ，\alpha ）$ 重核的反应速率基于 $（\alpha ，\gamma ）$亚库仑能量的横截面。这些速率对于模拟所谓的核合成至关重要$p$核。统计模型中的标准计算显示出对所选内容的极大敏感性$\alpha$-核势。本研究解释了这种虚假的尾巴导致这种巨大敏感性的原因。$\alpha$总反应截面的基础光学模型计算中的-核势。作为光学模型的替代方案，提出了一种简单的屏障传输模型。结果表明，这种简单的模型结合了精心选择的$\alpha$-核势能够预测总 $\alpha$诱导的反应截面，上面有各种各样的重目标核 $\mathrm{一种}\gtrsim 150$ 不确定性低于2倍。来自简单模型的新预测不需要对实验反应截面进行任何参数调整，而在先前的统计模型计算中，所有预测仍然非常不确定，因为 $\alpha$-核势必须调整为实验数据。新模型使我们能够预测天体重要的反应速率${}^{176}\mathrm{w\; ^}（\alpha ，\gamma ）{}^{180}\mathrm{操作系统}$减少不确定性的反应，导致低温下的反应速率大大降低。这种新方法也可以用于广泛的目标核$\mathrm{一种}\approx 60$ 取决于 $\mathrm{一种}\gtrsim 200$。