论文标题
R-Matrix理论Brune参数化中的影子杆
Shadow poles in Brune parametrization of R-matrix theory
论文作者
论文摘要
我们对核横截面的集体知识记录为核数据库中的共振参数。为了评估这些参数，测量运动的运动拟合了一个称为R-Matrix理论的核横截面的参数模型。为了删除Wigner-Eisenbud R-Matrix参数化中的任意边界参数，社区正在考虑将所有核数据库转换为Brune参数。在本文中，我们表明有比以前想象的要多的节奏参数。在通道阈值下方，我们证明存在两种类型的其他“阴影杆” - 分支阴影杆和分析阴影杆 - 取决于我们如何将R-Matrix运算符继续进行复杂的WaveNumbers（这样做，我们就建立了R-Matrix Operators的Mittag-Leffler扩展）。这需要比水平更多的节共振能量。但是，我们还证明，只要至少具有至少水平的数量，选择任何子集将产生相同的横截面。在实践中，这意味着可以从新的核数据库中丢弃影子弹杆。许多同位素通过帝国帝国近似进行评估，引入了复杂的共振能，以消除某些通道。我们概括了Brune的参数化，以涵盖Reich-Moore的近似值和附加的阴影杆，并表明所有Brune参数取决于我们选择继续将R-Matrix Operators继续进行复杂的WaveNumbers。为了将核数据库转换为Brune参数，核科学家社区必须首先决定这种惯例。作者主张支持分析延续。在Brune的R-Matrix理论的替代参数化中，阴影杆的第一个证据是在同位素Xenon-134，Spin-Parity组1/2（ - ）中观察到的。
Our collective knowledge of nuclear cross sections is recorded as resonance parameters in nuclear data libraries. To evaluate these parameters, campaigns of measurements are fitted with a parametric model of nuclear cross sections called R-matrix theory. In order to remove the arbitrary boundary parameters in the Wigner-Eisenbud R-matrix parametrization, the community is considering converting all nuclear data libraries to Brune parameters. In this article, we show there are more Brune parameters than previously thought. Below the channel threshold, we prove there exists two types of additional 'shadow poles' - branch shadow poles and analytic shadow poles - depending on how we continue R-matrix operators to complex wavenumbers (to do so we establish Mittag-Leffler expansions of R-matrix operators). This entails there are more Brune resonance energies than levels. Yet, we also prove that choosing any subset of Brune poles will yield the same cross sections than using the entire set of Brune poles, as long as it has at least the number of levels. In practice, this means that shadow Brune poles can be discarded from the new nuclear data libraries. Many isotopes are evaluated with the Reich-Moore approximation, introducing complex resonance energies to eliminate certain channels. We generalize Brune's parameterization to encompass the Reich-Moore approximation and the additional shadow poles, and show that all Brune parameters depend on what convention we choose to continue the R-matrix operators to complex wavenumbers. To convert nuclear data libraries to Brune parameters, the nuclear scientists community must thus first decide on such a convention. The authors argue in favor of analytic continuation. The first evidence of shadow poles in Brune's alternative parametrization of R-matrix theory is observed in isotope xenon-134, spin-parity group 1/2(-).
