Nuclear fission is hindered by dissipation. Using the stochastic Langevin model, we calculate the drop of fission cross sections caused by friction with respect to its standard statistical-model values, ${\sigma }_f^{\mathrm{drop}}$, as a function of the presadde dissipation strength $\left(\beta \right)$ for ${}^{226}\mathrm{U}$, ${}^{234}\mathrm{U}$, and ${}^{242}\mathrm{U}$. It is shown that the sensitivity of ${\sigma }_f^{\mathrm{drop}}$ to $\beta$ is substantially enhanced with increasing the isospin of the U fissioning system. Furthermore, we find that under typical conditions of excitation energy and angular momentum populating ${}^{240}\mathrm{U}$ (via radioactive beams) and ${}^{200}\mathrm{Tl}$ (via stable beams), the fission cross section of the high-isospin heavy ${}^{240}\mathrm{U}$ demonstrates a greater sensitivity to friction than that of the light ${}^{200}\mathrm{Tl}$. Our findings suggest that on the experimental side, to accurately probe presaddle dissipation with fission cross sections of heavy nuclei, it is useful to choose radioactive nuclear beams induced reactions as a way to populate excited heavy fissioning systems with high isospin.

中文翻译：

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重核裂变截面作为核耗散的探针

耗散阻碍了核裂变。使用随机Langevin模型，我们计算了相对于其标准统计模型值，由摩擦引起的裂变截面的下降，${\sigma }_F^{\mathrm{降低}}$，作为前驱耗散强度的函数 $（\beta ）$ 为了 ${}^{226}\mathrm{ü}$， ${}^{234}\mathrm{ü}$， 和 ${}^{242}\mathrm{ü}$。结果表明，${\sigma }_F^{\mathrm{降低}}$ 到 $\beta$通过增加U裂变系统的同位旋，可以大大提高水合态。此外，我们发现在典型的激发能和角动量条件下${}^{240}\mathrm{ü}$ （通过放射性束）和 ${}^{200}l$ （通过稳定梁），高等旋量重物的裂变截面 ${}^{240}\mathrm{ü}$ 表现出比光更大的摩擦敏感性 ${}^{200}l$。我们的发现表明，在实验方面，为了准确探测重核裂变截面的前驱耗散，选择放射性核束诱发的反应作为填充高同位旋高激发重裂变系统的一种方法是有用的。