核碰撞中粒子产生的同位旋依赖的动力学研究

The originally relativistic transport model and program are improved to include the isospin degree of freedom of nucleon and produced particle. One uses the isospin-distinguishable reaction cross sections and isospin-related interactions. At the same time, we adopt a quasi-particle picture including scalar and vector field from the chiral model, and build up the simulation of covariant kaon dynamics, in which the elementary kaon production cross sections according with new experimental data are used. This improved transport model is used to study carefully the observables of the K+ multiplicity, K+ flow and so on in intermediate-energy heavy-ion collisions. It is found from our calculated results that the improved dynamics model can reasonably describe new experimental data: the feature of the ratio of K+ multiplicities obtained in heavy (Au + Au) over light (C + C) systems as a function of the incident energy, the property of the K+ transvese flow, etc. This indicates that it is necessary to build up the covariant dynamics of nucleon and produced particle, to use reasonable reaction cross sections and interactions between particles, and to investigate in the dynamical processes of produced particles in order to evaluate rationally the signals probed in heavy ion collisions in a unified way. We also study the characteristics of particle production in heavy ion collisions at AGS, SPS and RHIC energies. We publish nine papers, in which one is published in Phys. Rev. Lett.. The task scheduled in this project supported by the funds is satisfactorily fulfilled.

研究奇异核间的碰撞和不对称核物质的态方程是当前核物理的前沿课题之一。探测核物质的性质和可能出现的物质新形态，一般通过研究核碰撞中产生粒子的末态特性来实现。而这些粒子的产生和输送过程是强的同位旋依赖关系的。我们拟做完全区分同位旋自由度的自洽反应动力学模拟，深入研究产生粒子的末态性质，以便提供更加真实可靠的探测信号。