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arXiv · 2509.09478

The role of near neutron drip-line nuclei in the $r$-process

T. Yu·Y. Y. Guo·X. F. Jiang·X. H. Wu
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Abstract

The role of near neutron-drip-line nuclei in the rapid neutron-capture process ($r$-process) is studied with the classical $r$-process model. Simulations under different astrophysical conditions ($T$, $n_n$) show that $r$-process paths approach the neutron-drip line under low-temperature and high-neutron-density conditions. A sensitivity study reveals that variations in the nuclear masses of these exotic nuclei significantly impact the abundances of superheavy nuclei, and lead to obvious abundance variations in the $A=110-125$, $A=175-185$, and $A=200-205$ regions. By contrast, the $r$-process rare-earth peak and the $A=130,195$ peaks remain largely unaffected. The nuclei that obviously impact $r$-process abundances are mainly distributed in the region of $25\leq Z\leq 90$ and $50\leq N\leq 180$, with the nuclei around neutron magic numbers found to be particularly important for the $r$-process, even in the near-neutron-drip-line region.

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T. Yu, Y. Y. Guo, X. F. Jiang, X. H. Wu. 2026-03-24. The role of near neutron drip-line nuclei in the $r$-process. https://doi.org/10.1088/1674-1137%2Fae4584

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