Two-neutron capture reactions and the r process
Two-neutron capture reactions and the r process
复制标题
双中子俘获反应和 r 过程
DOI：
10.1103/physrevc.74.015802
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发表时间：
2006
影响因子：
3.1
通讯作者：
J. Tostevin
中科院分区：
文献类型：
--
作者：
Amy J. Bartlett;J. Görres;G. Mathews;K. Otsuki;M. Wiescher;D. Frekers;A. Mengoni;J. Tostevin
计算了~ 4 He（2n，γ）~ 6 He和~ 6 He（α，n）~ 9 Be反应的速率，包括共振和非共振贡献.根据新的实验结果，对4 He的连续双中子俘获过程进行了重新评价。结果表明，一步双中子俘获反应可使连续双中子反应速率提高几个数量级。这开启了一种可能性，即通过4 He（2n，γ）6 He（α，n）9 Be的反应流可能与引发α过程并为r过程提供种子核的瓶颈三体反应4 He（2α，γ）12 C和4 He（αn，γ）9 Be竞争。在这里，我们探讨了这种双中子俘获对r过程核合成的影响。我们表明，这样的反应有最终丰度的影响不大，只会改变一个非常丰富的中子低温r过程中的r-过程丰度。
Rates for the 4He(2n, γ )6He and 6He(α, n)9Be reactions have been calculated, including both resonant and nonresonant contributions. The sequential two-neutron capture process on 4He has also been reevaluated on the basis of new experimental results. It is shown that a one-step dineutron capture reaction may enhance the sequential two-neutron reaction rate by several orders of magnitude. This opens the possibility that reaction flow through 4He(2n, γ )6He(α, n)9Be may occur in competition with the bottle-neck three-body reactions 4He(2α, γ )12C and the 4He(αn, γ )9Be that initiate the α process and provide seed nuclei for the r process. Here we explore the effect of such dineutron capture on r-process nucleosynthesis. We show that such reactions have little effect on the final abundance and would change only r-process abundances in an extremely neutron-rich low-temperature r process.