核物质对称能探测相关的理论研究

Recently, the studies of nuclear symmetry energy have attracted much attention in nuclear physics community. The symmetry energy, especially its slope around saturation densities, is crucial for understanding many interesting issues in both nuclear physics and astrophysics. Heavy-ion reactions induced by neutron-rich nuclei, especially radioactive beams, provide a unique opportunity to constrain the symmetry energy term in the EOS of isospin asymmetric nuclear matter. While comparing experimental data to theoretical calculations, due to many inputting uncertainties of transport model and experimental errors, it is absolutely not a trivial thing to study theoretical uncertainties. The cluster emission, the transport variables, the nucleon-nucleon cross section, the symmetry potential, the initialization, etc., all affect transport models to unscramble related experimental data. Considering the probe of nuclear symmetry energy has many uncertainties caused by several parts of the transport models while compared with the experimental data, we in this application try to give the uncertainties of probing the symmetry energy, which coming from different NN cross sections,different momentum dependence of nuclear symmetry potential as well as different transport models. These studies will help us to translate experimental data more scientifically. In the mean time, we will study the origins of uncertainties of NN cross sections and nuclear symmetry energy, nuclear symmetry potential based on BHF approach. And we try to find more sensitive probe of nuclear symmetry energy from sub-threshold meson production in heavy-ion collisions. At last, U-boson related questions in heavy-ion collisions will be explored.

非对称核物质状态方程，尤其是核物质对称能的高密行为是当前核物理及核天体物理研究中的一个重要的但悬而未决问题。然而，由于不同的输运模型对现今有限的核反应实验数据的解读存在巨大差异， 导致人们对核物质对称能的密度依赖性（尤其是其高密行为）依然没有定性的认识。本项目拟在研究核子核子相互作用的不确定性的基础上，探索如何尽可能避免由于输运模型计算的不确定性而导致的对实验数据的错误解读，甚至错误的定性解读，从而提高人们对相关核实验数据解读的可信性，得出较为正确的对称能密度依赖性的信息。另外，本申请还将研究对称能探测相关的高敏感探针以及高密压缩物质产生中可能的U-boson与核子相互作用对核物质性质探测的影响。

对称能的高密行为具有较大的理论与天文研究意义，由于它的高度的不确定性，在当前世界各地的实验室都有对称能探测相关的研究计划。我们主要研究了对称能探测相关的各种理论的不确定性，比如重子势，pion介子势，非弹性散射截面的不确定性，以及各种介质效应对对称能探测的影响，研究了核子核子短程关联效应的影响；我们提出高密对称能探测的定性探测方法。这些研究对于对称能高密行为的最终确定具有重要意义。