Nuclear matter and neutron-star properties calculated with the Skyrme interaction
Nuclear matter and neutron-star properties calculated with the Skyrme interaction
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DOI：
10.1103/physrevc.68.034324
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发表时间：
2003-09
影响因子：
3.1
通讯作者：
J. Stone;J. Miller;R. Koncewicz;P. Stevenson;M. Strayer
中科院分区：
文献类型：
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作者：
J. Stone;J. Miller;R. Koncewicz;P. Stevenson;M. Strayer
几十年来，有效的 Skyrme 相互作用已在平均场模型中广泛使用，并且已经提出了许多不同的相互作用参数化。所有这些都与核基态的实验观测值以及饱和密度 n0 下无限对称核物质的性质相一致。然而，当应用于更广泛的密度范围（高达〜3n0）时，他们预测对称和不对称核物质的可观察量的行为会有很大不同。自然存在的不对称核物质的一个特别相关的例子是构成中子星的材料。在核物质密度附近，这可以很好地表示为 β 平衡中的中子、质子、电子和 μ 子（n+p+e+μ 物质）的混合物，这些密度被证明是确定质量接近广泛使用的“规范”值 1.4M⊙ 的中子星模型特性的关键密度。通过使用不同的 Skyrme 参数化构建中子星物质的状态方程，计算相应的中子星模型，然后将其与观测数据进行比较，可以获得 Skyrme 参数值的附加约束。这样的约束特别重要，因为参数化最初是通过拟合双闭壳核的性质来确定的，并且它们对于具有高同位旋值的核（例如中子滴线及以外的核）的适用程度是一个悬而未决的问题。中子星环境为此提供了宝贵的试验场。我们对 87 种不同的 Skyrme 参数化进行了研究，以检验它们在预测无限核物质的预期特性和生成合理的中子星模型方面的成功程度。这是对核物质特征可观测值的密度依赖性的各种 Skyrme 参数化预测的首次系统研究； β-平衡物质的对称能量的密度依赖性被证明是一个关键属性，用于指示哪些 Skyrme 参数集同样适用于有限核和中子星物质。在所研究的 87 个参数化中，只有 27 个通过了令人满意的中子星模型的测试，我们列出了其中的列表。
The effective Skyrme interaction has been used extensively in mean-field models for several decades and many different parametrizations of the interaction have been proposed. All of these give similar agreement with the experimental observables of nuclear ground states as well as with the properties of infinite symmetric nuclear matter at the saturation density n0. However, when applied over a wider range of densities (up to ∼3n0) they predict widely varying behavior for the observables of both symmetric and asymmetric nuclear matter. A particularly relevant example of naturally occurring asymmetric nuclear matter is the material of which neutron stars are composed. At around nuclear matter density, this can be well represented as a mixture of neutrons, protons, electrons, and muons (n+p+e+μ matter) in β-equilibrium, and these densities turn out to be the key ones for determining the properties of neutron-star models with masses near to the widely used “canonical” value of 1.4M⊙. By constructing equations of state for neutron-star matter using the different Skyrme parametrizations, calculating corresponding neutron-star models and then comparing these with observational data, an additional constraint can be obtained for the values of the Skyrme parameters. Such a constraint is particularly relevant because the parametrizations are initially determined by fitting to the properties of doubly closed-shell nuclei and it is an open question how suitable they then are for nuclei with high values of isospin, such as those at the neutron drip-line and beyond. The neutron-star environment provides an invaluable testing ground for this. We have carried out an investigation of 87 different Skyrme parametrizations in order to examine how successful they are in predicting the expected properties of infinite nuclear matter and generating plausible neutron-star models. This is the first systematic study of the predictions of the various Skyrme parametrizations for the density dependence of the characteristic observables of nuclear matter; the density dependence of the symmetry energy for β-equilibrium matter turns out to be a crucial property for indicating which Skyrme parameter sets will apply equally well for finite nuclei and for neutron-star matter. Only 27 of the 87 parametrizations investigated pass the test of giving satisfactory neutron-star models and we present a list of these.