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arXiv 1204.2644nucl-th
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有限核相对论平均场模型对中子星物质的优化

Optimization of relativistic mean field model for finite nuclei to neutron star matter

B. K. Agrawal, A. Sulaksono, P. -G. Reinhard

摘要:

我们用一组选定的全局观测量优化了扩展相对论平均场模型的参数,这些观测量包括沿几个同位素和等规链的核的结合能和电荷半径,以及$^{90}$ Zr和$^{208}$ Pb核的等标巨共振能.模型参数进一步受到稀中子物质的单位中子能量和超核密度下对称和非对称核物质状态方程的约束。得到了两个新的参数集BSP和IUFSU*,其中一个是最近提出的IUFSU参数集的变体。BSP参数化利用$ω$和$σ$介子之间的四阶交叉耦合来模拟状态方程的高密度行为,而不是像IUFSU* 或IUFSU那样利用$ω$介子自耦合。我们的参数集产生显着的改进,结合能系统和状态方程的稀中子物质。四阶$ω-σ$交叉耦合项的扩展RMF模型的重要性,往往被忽视,实现。

英文摘要:

We have optimized the parameters of extended relativistic mean-field model using a selected set of global observables which includes binding energies and charge radii for nuclei along several isotopic and isotonic chains and the iso-scalar giant monopole resonance energies for the $^{90}$Zr and $^{208}$Pb nuclei. The model parameters are further constrained by the available informations on the energy per neutron for the dilute neutron matter and bounds on the equations of state of the symmetric and asymmetric nuclear matter at supra-nuclear densities. Two new parameter sets BSP and IUFSU* are obtained, later one being the variant of recently proposed IUFSU parameter set. The BSP parametrization uses the contributions from the quartic order cross-coupling between $ω$ and $σ$ mesons to model the high density behaviour of the equation of state instead of the $ω$ meson self-coupling as in the case of IUFSU* or IUFSU. Our parameter sets yield appreciable improvements in the binding energy systematics and the equation of state for the dilute neutron matter. The importance of the quartic order $ω-σ$ cross coupling term of the extended RMF model, as often ignored, is realized.

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