The study of Quark-Gluon-Plasma in ultrarelativistic nuclear Collisions

研究与取得的成果研究了160GeV左右能量的pb-pb碰撞形成的温度和密度，并利用该合作开发的事件发生器研究了160GeV能量的pb-pb碰撞形成的碰撞复合体的热化。与CIAE合作进行了模拟和分析。主要结果有：(1)在10^<@62>(-13)秒后发生热化。(2)达到的温度为80-110 MeV，持续时间约为3*10^<@62>(1-13)秒。(3)达到的密度为10^<@62> (39)/cm^<@62>3.2。研究了双粒子干涉测量得到的粒子源尺寸与时空参数的关系，利用事件发生器对实际时空扩展与干涉测量实验得到的时空参数进行了比较。主要结果是：(1)由于相对论的性质，干涉测量实验无法观测到整个时空的延伸。(2)动量限制造成严重的差异。(3)这是典型的纵向延伸。这些结果已由吕廷德（t.d. Lu， CIAE）在广岛的访问中进行了总结。无取向手性凝聚体的双粒子干涉测量理论研究了无取向手性凝聚体的双粒子分布。结果表明：(1)多dcc域情况下的双介子相关公式。(2)异介子对也有相关性。(3)不同介子在动量小且相反的情况下是相关的。Muroya与b.h. Sa和y.m.z z .4一起访问了CIAE，进一步扩展了本研究。有限密度下手性相变附近重子磁化率的研究用nambujana - lasinio模型计算了夸克-胶子等离子体手性相变附近重子磁化率。在有限密度下，发现了它的异常增强。对它在早期宇宙高能核碰撞和核合成中的意义的研究仍在继续。

Research and obtalned results1. Study of temperature and density formed by the pb-pb collisions at energies around 160 GeV/nucleonThermalization of collision complex formed by pb-pb collisions at 160GeV is studied by an event generator developed in this collaboration.Simulations and analysis have been carried out in collaboration with CIAE.Main results are : (1) Thermalization undergoes after 10^<@62> (-13) second. (2) Achieved temperature is 80-110 MeV and its duration is about 3*10^<@62> (1-13) second. (3) Achieved density is 10^<@62> (39) /cm^<@62>3.2. Study of the relationsip between particle source size and space-time parameters obtained by two particle interferometryReal space-time extension and space-time parameters obtained by nterferometry experiment are compared by the use of event generator. Main results are : (1) Because of relativistic nature, whole space-time extension can not be observed by a interferometry : experiment. (2) Momentum restriction causes serious difference. (3) This is typically seen in longitudinal extension. These results have been summarized by T.D Lu (CIAE) in his visit at Hiroshima.3. Theory of two particle interferometry with disoriented chiral condensateTwo particle distribution from disoriented chiral condensate hnd been studied by T.D Lu, Muroya, Miyamura and Hioki. Results are : (1) Formula for two pion correlation in the case of many dcc domains. (2) Unlike pion pair has also correlation. (3) Unlik pions are correlated in the case of small and opposite momenta. This research has been extended by the visiting of Muroya at CIAE with B.H Sa and Y.M.Zheng.4. Study of baryonic susceptibility near the chiral phase transition at finite densityBaryonic susceptibility near chiral transition of quark-gluon plasma has calculated by Nambu-Jona-Lasinio model. At finite density, anomalous enhancement of it has been found. Study of implications of it in high energy nucleus collision and nucleosynthesis in early universe is now continuing.