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arXiv 1706.05024nucl-th
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利用TDHF研究同位旋非对称核物质的输运性质

Transport properties of isospin asymmetric nuclear matter using TDHF

A. S. Umar, C. Simenel, W. Ye

摘要:

背景资料:核的深度非弹性反应的研究提供了一个工具,研究核输运现象的全方位的平衡动力学。这些查询为我们提供了模拟这种现象的成分,并帮助回答有关核状态方程(EOS)及其作为中子与质子$(N/Z)$比的函数的演化的重要问题。目的:其动机是从微观角度研究核输运现象的实时动力学及其对$(N/Z)$不对称性的依赖性,以避免对所涉及过程的任何预先设想的假设。方法:用含时Hartree-Fock(TDHF)方法计算了8.5 MeV $/A$能量下$^{78}$ Kr+ $^{208}$ Pb和$^{92}$ Kr+ $^{208}$ Pb体系的深部非弹性反应.计算了相关观测量的影响参数和能量损失依赖性。此外,采用密度约束TDHF方法计算了初级碎片的激发能。统计去激代码GEMINI用于检查最终反应产物。结果:计算了动能损失和粘附时间随冲击参数的变化关系。计算碎片的最终性质(电荷、质量、散射角、动能)。结论:我们发现一个平稳的依赖性的能量损失,$E_\mathrm{loss}$,对这两个系统的影响参数。另一方面,对于低$E_\mathrm{loss}$值,两个系统的传输特性非常不同,但在较高的$E_\mathrm{loss}$状态下变得相似。电荷平衡过程的平均寿命(由碎片的最终$(N-Z)/A$值获得)显示为$\sim 0.5$ ~zs。这个值比费米能量下反应得到的值稍大(但数量级相同)。

英文摘要:

Background: The study of deep-inelastic reactions of nuclei provide a vehicle to investigate nuclear transport phenomena for a full range of equilibration dynamics. These inquires provide us the ingredients to model such phenomena and help answer important questions about the nuclear Equation of State (EOS) and its evolution as a function of neutron-to-proton $(N/Z)$ ratio. Purpose: The motivation is to examine the real-time dynamics of nuclear transport phenomena and its dependence on $(N/Z)$ asymmetry from a microscopic point of view to avoid any pre-conceived assumptions about the involved processes. Method: Time-dependent Hartree-Fock (TDHF) method in full 3D is employed to calculate deep-inelastic reactions of $^{78}$Kr+$^{208}$Pb and $^{92}$Kr+$^{208}$Pb systems at 8.5~MeV$/A$. The impact parameter and energy-loss dependence of relevant observables are calculated. In addition, density constrained TDHF method is used to compute excitation energies of the primary fragments. The statistical deexcitation code GEMINI is utilized to examine the final reaction products. Results: The kinetic energy loss and sticking times as a function of impact parameter are calculated. Final properties of the fragments (charge, mass, scattering angle, kinetic energy) are computed. Conclusions: We find a smooth dependence of the energy loss, $E_\mathrm{loss}$, on the impact parameter for both systems. On the other hand the transfer properties for low $E_\mathrm{loss}$ values are very different for the two systems but become similar in the higher $E_\mathrm{loss}$ regime. The mean life time of the charge equilibration process, obtained from the final $(N-Z)/A$ value of the fragments, is shown to be $\sim 0.5$~zs. This value is slightly larger (but of the same order) than the value obtained from reactions at Fermi energies.

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