Influence of transport variables on isospin transport ratios
Influence of transport variables on isospin transport ratios
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DOI：
10.1103/physrevc.84.054603
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发表时间：
2011-07
影响因子：
3.1
通讯作者：
D. Coupland;W. G. Lynch;M. Tsang;P. Danielewicz;Y. Zhang
中科院分区：
文献类型：
--
作者：
D. Coupland;W. G. Lynch;M. Tsang;P. Danielewicz;Y. Zhang
核状态方程中的对称能影响着核天体物理、核结构和核反应的许多方面。最近来自重离子碰撞的约束，包括同位旋扩散观测，已经开始对核饱和密度以下的对称能施加约束，但这些约束取决于所采用的输运模型和输入物理，而不是对称能。为了理解这些依赖关系，我们研究了对称能、等尺度平均场压缩率和动量依赖、介质中核子-核子截面和光团簇产生对pBUU输运码内同位旋扩散的影响。除了对称能之外，还有几个不确定的问题强烈地影响同位旋扩散，最明显的是截面和团簇的产生。此外，计算的同位旋输运比存在差异，这取决于它们是使用残基还是所有向前移动的碎片的同位旋不对称来计算的。比较这两个量的同位旋输运比的测量将有助于对输入物理进行约束，例如对称能的密度依赖性。
The symmetry energy in the nuclear equation of state affects many aspects of nuclear astrophysics, nuclear structure, and nuclear reactions. Recent constraints from heavy ion collisions, including isospin diffusion observables, have started to put constraints on the symmetry energy below nuclear saturation density, but these constraints depend on the employed transport model and input physics other than the symmetry energy. To understand these dependencies, we study the influence of the symmetry energy, isoscaler mean field compressibility and momentum dependence, in-medium nucleon-nucleon cross sections, and light cluster production on isospin diffusion within the pBUU transport code. In addition to the symmetry energy, several uncertain issues strongly affect isospin diffusion, most notably the cross sections and cluster production. In addition, there is a difference in the calculated isospin transport ratios, depending upon whether they are computed using the isospin asymmetry of either the residue or of all forward moving fragments. Measurements that compare the isospin transport ratios of these two quantities would help place constraints on the input physics, such as the density dependence of the symmetry energy.