Theoretical Nuclear Physics

9509266 Ko在相对论速度下的核-核碰撞中，可以产生一块温度和密度类似于大爆炸后早期宇宙和中子星内部的物质。在这个方案中，我们将使用有效拉格朗日和基于量子色动力学的模型来研究这种热的致密物质的性质。特别是，我们将研究有限密度和温度下的强子质量和耦合，因为它们预计会在介质中发生重大修改。将这些介质效应包括在相对论输运模型中，可以真实地描述目前加速器可用的能量下的重离子碰撞。对这些碰撞产生的双轻子的研究将提供关于热致密物质性质的直接信息，因为物质中的双轻子相互作用相对较弱。奇异粒子的产生也将被研究，因为它们提供了另一个有希望的探测器，作为奇异性守恒的结果，热致密物质。我们的长期目标是将相对论输运模型扩展到包括夸克和胶子自由度，这样人们就可以描述未来相对论重离子对撞机上的核碰撞，在未来的相对论重离子对撞机中，预计会在初始阶段形成夸克-胶子等离子体。这项拟议的研究使鉴定夸克-胶子等离子体的存在和研究其性质成为可能。***

9509266 Ko In nucleus-nucleus collisions at relativistic velocities, a piece of matter with temperature and density similar to that in the early universe after the Big Bang and the interior of neutron stars can be created. In this proposal, we shall investigate the properties of this hot dense matter using both effective Lagrangians and models that are based on the quantum chrodynamics. In particular, hadron masses and couplings at finite densities and temperatures will be studied since they are expected to be significantly modified in a medium. Including these medium effects in the relativistic transport model allows a realistic description of heavy ion collisions at energies available from present accelerators. The study of dilepton production from these collisions will then provide direct information on the properties of the hot dense matter due to the relatively weak interactions of dileptons in matter. The production of strange particles will also be investigated as they offer another promising probe of the hot dense matter as a result of strangeness conservation. Our long range goal is to extend the relativistic transport model to include the quark and gluon degrees of freedom so that one can describe nuclear collisions at future relativistic heavy ion colliders in which a quark-gluon plasma is expected to be formed in the initial stage. the proposed study makes it possible to identify the existence of the quark-gluon plasma and to study its properties. ***