论文标题
Gamow Shell模型的辐射捕获反应的描述$^8 $ LI $（N，γ）$$^9 $ LI
Gamow shell model description of the radiative capture reaction $^8$Li$(n,γ)$$^9$Li
论文作者
论文摘要
$^8 $ li $（n，γ）$$^9 $ li反应在几个反应链中起着至关重要的作用，导致$ a> 12 $ nuclei的核合成。由于$^8 $ li的不稳定性质和中子目标的不可用，因此对该反应的直接测量非常困难。到目前为止，仅通过间接实验提供了此横截面的上限。在这项工作中，我们使用耦合通道表示（GSM-CC）中的Gamow Shell模型（GSM）来研究$^9 $ li的属性和辐射捕获反应$^8 $ li $（n，γ）$$^9 $ li。在GSM-CC计算中，使用了一个有限的两体相互作用，用于重现$^{8-9} $ li的低能光谱。在计算$^8 $ li $（n，γ）$$^9 $ li横截面中，所有相关的E1，M1和E2从初始连续性状态到最终键状态$ {3/2} _1^ - $，$ {1/2} _1/2} _1^ - $ and $ {3/2} _1^ - $，$ {1/2} _1^ - us usonance $ resoonance $ resonance $ {$ {5/2} _1 $ nes $ nes $^$^$^$^$^$^$^$^$^$^$^ - GSM-CC方法在$^9 $ li中重现了实验性低能频谱，中子发射阈值和光谱因子。计算出的反应速率与在恒星能量的间接测量中获得的反应速率的实验上限一致。 GSM-CC的计算表明，$^8 $ li $（n，γ）$^9 $ li反应可以通过主链$^7 $ li（$ n，γ$）$^8 $ li（$α，n $）$^{11} $^{11} $ b（$ n，γ$^$^$^{12} $^{12} $ b（$^$ b（$ b（$ b（$^），对计算的横截面的重大贡献是由直接的E1过渡到$^8 $ li的基础状态给出的。激发态对反应速率的贡献不超过$ \ sim $ 18％的总反应率的18％。
The $^8$Li$(n,γ)$$^9$Li reaction plays a critical role in several reaction chains leading to the nucleosynthesis of $A>12$ nuclei. Due to unstable nature of $^8$Li and the unavailability of neutron targets, direct measurements of this reaction are exceedingly difficult. Only upper limits of this cross section, provided by the indirect experiments, have been obtained so far. In this work, we use the Gamow shell model (GSM) in the coupled-channel representation (GSM-CC) to study the properties of $^9$Li and the radiative capture reaction $^8$Li$(n,γ)$$^9$Li. In GSM-CC calculations, a translationally invariant Hamiltonian is used with a finite-range two-body interaction tuned to reproduce the low-energy spectra of $^{8-9}$Li. In the calculation of $^8$Li$(n,γ)$$^9$Li cross section, all relevant E1, M1, and E2 transitions from the initial continuum states to the final bound states ${3/2}_1^-$, ${1/2}_1^-$ and the resonance ${5/2}_1^-$ of $^9$Li are included. The GSM-CC approach reproduces the experimental low-energy spectrum, neutron emission threshold, and spectroscopic factors in $^9$Li. The calculated reaction rate is consistent with the experimental upper limit of the reaction rate obtained in the indirect measurements at stellar energies. The GSM-CC calculations suggest that the $^8$Li$(n,γ)$$^9$Li reaction can reduce heavy-element production via the main chain $^7$Li($n,γ$)$^8$Li($α,n$)$^{11}$B($n,γ$)$^{12}$B($β^+$)$^{12}$C. Major contribution to the calculated cross section is given by the direct E1 transition to the ground state of $^8$Li. The contribution of excited states to the reaction rate does not exceed $\sim$18% of the total reaction rate.
