基于中能重离子碰撞研究高密对称能

用于描述核物质中子质子单粒子能量之差的对称能，最近20年得到了核物理学界的广泛关注。在饱和核密度附近，对称能的数值及斜率基本得到约束，然而其高密行为至今仍具有很大的不确定性。当前，探测对称能的研究计划正在世界范围内能够提供放射性束流的实验室展开。伴随着对称能相关实验的规划、进行，发展更加先进的同位旋依赖的输运理论模型变得非常必要。我们将核子-核子短程关联及介质中同位旋依赖的重子-重子非弹性散射截面等研究的新进展融入到了同位旋依赖的输运模型里面；探索了新的敏感于高密对称能的可观测量，比如挤出核子的中质比、光子、轻碎片，以及包含奇异隐奇异夸克的介子产生等；提出了高密对称能探测盲点的问题并给出解决办法；对于常见的对称能敏感观测量的模型预言的不确定性进行了彻底细致的研究；提出采用定性观测量，比如高能出射粒子的中质比，将高密对称能进行定性约束；率先提出并研究了对称能敏感观测量的探测密度区间问题，指出对称能敏感观测量的探测密度往往小于核反应最大压缩密度；发现核子-核子短程关联明显削弱观测量的对称能效应；考虑到饱和点处对称能斜率的约束范围，基于输运模型，提出通过探测对称能的曲率来约束高密对称能。除了利用重离子碰撞约束高密对称能之外，人们也可以通过与中子星相关的大量天体观测来间接约束高密对称能。

Probing High-density Symmetry Energy Using Heavy-ion Collisions at Intermediate Energies

The nuclear symmetry energy, which describes the energy difference of per proton and neutron in nuclear matter, has been extensively studied within the last two decades. Around saturation density, both the value and the slope of the nuclear symmetry energy have been roughly constrained, its high-density behavior is now still in argument. Probing high-density symmetry energy at terrestrial laboratories is being carried out at facilities that offer radioactive beams worldwide. While relevant experiments are being conducted, we theoretically developed more advanced isospin-dependent transport model including new physics such as nucleon-nucleon short-range correlations and in-medium isospin-dependent baryon-baryon scattering cross section. New sensitive probes of the high-density symmetry energy are provided, such as squeezed-out neutron to proton ratio, photon and light cluster as well as the production of mesons with strangeness or hidden strangeness. The blind spots of probing the high-density symmetry energy by sensitive observable are demonstrated. Model dependences of frequently used sensitive probes of the symmetry energy have been studied thoroughly based on different transport models. A qualitative observable of neutron to proton ratio at high kinetic energy is proposed to probe the high-density symmetry energy qualitatively. The probed density regions of the symmetry energy by some observables are first studied and usually lower probed density regions comparing with maximum compression density are obtained. Nucleon-nucleon short-range correlations usually reduce values of sensitive observables of the symmetry energy. Probing the curvature of the symmetry energy by involving the slope information of the symmetry energy at saturation point in the transport model is proposed. Besides constraining the high-density symmetry energy by using heavy-ion collisions, a lot of neutron-star related observations from heaven may also be used to constrain the high-density symmetry energy.