论文标题

$ {}^{12} $ C+$ {}^{12} $ C Fusion反应的$ {}^{12}的修饰天体S因子

The modified astrophysical S-factor of the ${}^{12}$C+${}^{12}$C fusion reaction at sub-barrier energies

论文作者

Li, Y. J., Fang, X., Bucher, B., Li, K. A., Ru, L. H., Tang, X. D.

论文摘要

$^{12} $ C+$^{12} $ c Fusion反应在恒星进化和爆炸中起着至关重要的作用。它的开放反应频道主要包括$α$,$ p $,$ n $和$ {}^{8} $ be。尽管努力超过半个世纪,但在使用各种技术测量的实验数据中仍然存在巨大差异。在这项工作中,我们使用统计模型分析现有数据。我们的计算表明:1)随着预测比率的增加,预测的分支比率的相对系统不确定性变小; 2)$ p $和$α$通道的总经过修改的天体S因子(S $^*$因素),可以通过总结其相应地基状态过渡的S $^*$因子以及特征性的$γ$ rays的s $^*$因子,同时考虑到缺失通道对后者的贡献。在基于统计模型预测的分支比率进行校正之后,在$ {e} _ {cm}> $ 4 MEV的不同数据集之间达成了一项协议,而某些差异仍处于较低的能量,这表明需要在不久的将来进行更好的测量。我们发现,从间接测量中获得的最近的S $^*$因子与低于2.6 MeV的能量的直接测量不一致。我们建议$ {}^{12} $ C+$ {}^{12} $ c s $^*$ factor的上限和下限。还建议使用新的$^{12} $ C+$^{12} $ C反应率。

The $^{12}$C+$^{12}$C fusion reaction plays a crucial role in stellar evolution and explosions. Its open reaction channels mainly include $α$, $p$, $n$, and ${}^{8}$Be. Despite more than a half century of efforts, large discrepancies remain among the experimental data measured using various techniques. In this work, we analyze the existing data using the statistical model. Our calculation shows: 1) the relative systematic uncertainties of the predicted branching ratios get smaller as the predicted ratios increase; 2) the total modified astrophysical S-factors (S$^*$ factors) of the $p$ and $α$ channels can each be obtained by summing the S$^*$ factors of their corresponding ground-state transitions and the characteristic $γ$ rays while taking into account the contributions of the missing channels to the latter. After applying corrections based on branching ratios predicted by the statistical model, an agreement is achieved among the different data sets at ${E}_{cm}>$4 MeV, while some discrepancies remain at lower energies suggesting the need for better measurements in the near future. We find that the recent S$^*$ factor obtained from an indirect measurement is inconsistent with the direct measurement at energies below 2.6 MeV. We recommend upper and lower limits for the ${}^{12}$C+${}^{12}$C S$^*$ factor based on the existing models. A new $^{12}$C+$^{12}$C reaction rate is also recommended.

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