守恒荷的涨落与关联和强相互作用物质相结构的理论研究及相关实验信号分析

The fluctuations and correlations of conserved charges are the most sensitive probes for the phase transition of strongly interacting matter. The RHIC beam energy scan experiments and the more precise measurements at 2019 provide a very important opportunity to explore the QCD phase transition and phase structure.. With the combination of the RHIC beam energy scan experiments, in this project we will investigate the influence of the interaction between Polyakov loop dynamics and chiral condensate in hot and dense medium on the QCD transitions, and analyze the relations between QCD transition, the fluctuations and correlations of conserved charges, as well as chemical freeze-out conditions (collision energies). We will explain the non-monotonic behavior of the kurtosis of net-proton number fluctuations discovered in experiments. We will study the fluctuations and correlations of conserved charges induced by the spinodal structure of the non-equilibrium first-order transition. By comparing them with the first-order transition in equilibrium and the critical fluctuations, we will look for the signals to distinguish different transitions. Utilizing the fluctuations of conserved charges in the non-central collisions in heavy collision experiments, we will study the inverse magnetic catalysis of chiral transition at high temperature, check the mechanisms of inverse magnetic catalysis, and obtain the QCD phase diagram under magnetic fields. The investigations in the project are very meaningful for deeply understanding the phase transition and phase structure of QCD, as well as the relevant analysis of experimental signals.

守恒荷的涨落与关联是研究强相互作用物质相变最敏感的探针，RHIC的能量扫描实验及2019年计划进行的更精确测量为研究QCD的相变与相结构提供了重大机遇。. 本项目将结合RHIC的能量扫描实验，研究Polyakov圈动力学和手征凝聚在热密介质中的相互作用对QCD相变的影响，揭示QCD相变、守恒荷的涨落和化学冻出条件（碰撞能量）之间的关系，解释实验上发现的净质子数分布的峰度随碰撞能量的非单调行为。研究非平衡态一阶相变的spinodal structure引起的涨落与关联，并与平衡态的一阶相变、临界涨落相比较，寻找区分不同相变的信号。利用非中心碰撞实验中守恒荷的涨落分布，研究高温手征相变的磁反催化效应，并对磁反催化机制进行检验，获得磁场下QCD的相图。本项目的开展对深入理解QCD的相变与相结构及相关实验信号分析具有重要的参考意义。

守恒荷的涨落与关联是研究强相互作用物质相变的敏感探针，RHIC的能量扫描实验为研究QCD的相变和相结构提供重了要机遇。与重离子碰撞实验相结合，本项目（1）研究了平滑过渡、一阶相变、临界区域的净重子数、电荷数和奇异数的涨落以及这些守恒荷之间的关联涨落，分析了化学冻结时的涨落分布与碰撞能量之间的关系，给出了相关的实验信号。（2）探讨了一阶相变伴随的spinodal结构对守恒荷的涨落和关联的影响，并与平衡态的一阶相变、临界涨落进行了比较，讨论了对观测信号的潜在影响。（3）研究了磁场对QCD相结构和守恒荷之间关联涨落的影响，发现磁场存在时朗道量子化可以导致低温QCD物质存在复杂的相结构。（4）研究了强子间的相互作用，特别是核物质的气液相变引起的重子数涨落及其与碰撞能量的关系，相关结果有可能解释RHIC在碰撞能量为3GeV时的数据。（5）研究了动量各项异性分布对QCD相结构的影响及其引起的重子数涨落在不同碰撞能量下的演化行为。除此之外，探讨了声速与QCD相变的关系。本项目的研究及后续进展有助于探索QCD相结构及相关实验信号分析。