Analysis of the total 12C(α,γ)16O cross section based on available angular distributions and other primary data
Analysis of the total 12C(α,γ)16O cross section based on available angular distributions and other primary data
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根据可用的角度分布和其他主要数据分析总 12C(α,γ)16O 横截面
DOI：
10.1103/physrevc.54.393
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发表时间：
1996
影响因子：
3.1
通讯作者：
K. Langanke
中科院分区：
文献类型：
--
作者：
L. Buchmann;R. Azuma;C. Barnes;J. Humblet;K. Langanke
由于了解12 C/16 O的比值对于理解大质量恒星的后期演化至关重要，因此我们利用12 C上的辐射α捕获和弹性α散射的角分布数据完成了新的R-和K-矩阵拟合。本文报道了恒星能量下~（12）C（α，γ）~（16）O总速率的估算。与以前的工作相比，分析通常涉及直接对原始数据进行R矩阵和K矩阵拟合，即，与能量和角度相关的微分产生，同时拟合所有相关的分波（这里称为表面拟合）。结果表明，虽然最近的16 N β延迟α粒子衰变实验很好地限制了反应的E1部分，但E2基态截面因子只能有上限，我们保守地认为SE 2（300）<140 keV B.然后进行模拟，以探索什么样的新数据可以导致对SE 2（300）的更好限制。我们发现，改进的弹性散射数据可能是这种限制的最佳短期候选者，而用新的辐射捕获数据显着提高S（300）可能需要更长期的努力。然后讨论了12 C（α，γ）16 O的E2部分的α-转移反应的理论模型和估计，以与本工作的R-和K-矩阵拟合进行比较。
Because a knowledge of the 12C/16O ratio is crucial to the understanding of the later evolution of massive stars, new R- and K-matrix fits have been completed using the available angular distribution data from radiative α capture and elastic α scattering on 12C. Estimates of the total 12C(α,γ)16O rate at stellar energies are reported. In contrast with previous work, the analyses generally involve R- and K-matrix fits directly to the primary data, i.e., the energy- and angle-dependent differential yields, with all relevant partial waves fitted simultaneously (referred to here as surface fits). It is shown that, while the E1 part of the reaction is well constrained by a recent experiment on the β-delayed α-particle decay of 16N, only upper limits can be placed on the E2 ground state cross section factor which we take conservatively as SE2(300)<140 keV b. Simulations were then carried out to explore what kind of new data could lead to better restrictions on SE2(300). We find that improved elastic scattering data may be the best short-term candidate for such restrictions while significantly improving S(300) with new radiative capture data may require a longer-term effort. Theoretical models and estimates from α-transfer reactions for the E2 part of 12C(α,γ)16O are then discussed for comparison with the R- and K-matrix fits of the present work.