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Theoretical study of beauy-ins collisions at exirame high enngiro

Exirame High Enngiro 的 Beauy-ins 碰撞理论研究

基本信息

批准号：
06640394
负责人：
MATSUI Tetsuo
金额：
$ 1.34万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

We conducted a theoretical research on the expected properties of dense matter produced in ultra-relativistic heavy ion collisions and their experimental probes. Progress has been made in the following problems :1) Shadowing effects in pion interferometry : It is well known that the momentum correlation between a pair of identical particles produced in high energy collisions can be used to extract information on trhe space-time geometry of the particle source. We studied how such correlation is affected by the final state interaction between the pions and the pions source itself. It was found that if the pions are emitted from a strong souce, such as a quark-gluon-plasma, the source acts as a strong absorber of pions and this may result in suppression of the momentum correlations at small relative momenta of pions.2) Chiral phase transition at finite temperature in the linerar sigma model : We studied the chiral phase transition in equilibrium using the linear sigma model in a self-consistent Hartree approximation. Previous works had encountered difficulties of violating Goldstone's theorem in the chiral limit. We formulated a new self-consistent approximation scheme which respects the Goldstone theorem explicitly. It was shown that in this approximation the theory predicts a (weak) first order phase transition in the chiral limit due to the long range fluctuations of meson field whose effective masses become small in the transition region.3) Variational approach for dynamics of expanding quantum fields : We descibed the dynamics of expanding quantum fields in terms of variational wave functional in the functional Schrodinger picture. The variational wavefunctional is chosen in a generalized gaussian form, as for the free field. We constructed a family of boost in variant solutions to the equations of motion derived by the variational principle.

对超相对论重离子碰撞产生的致密物质的预期性质及其实验探测器进行了理论研究。在以下问题上取得了进展：1)介子干涉测量中的阴影效应：众所周知，在高能碰撞中产生的一对相同粒子之间的动量关联可以用来提取粒子源的时空几何信息。我们研究了介子与介子源之间的最终态相互作用如何影响这种相关性。研究发现，如果介子从强源（如夸克-胶子-等离子体）发射，则该源对介子起强烈的吸收作用，这可能导致介子在相对动量较小时的动量相关性受到抑制。2)线性sigma模型有限温度下的手性相变：采用自洽Hartree近似下的线性sigma模型研究了平衡态手性相变。以往的研究在手性极限中遇到了违反戈德斯通定理的困难。我们给出了一个新的符合Goldstone定理的自洽近似格式。结果表明，在此近似下，由于介子场的长范围波动，其有效质量在过渡区变小，该理论预测了手性极限的（弱）一阶相变。3)扩展量子场动力学的变分方法：在泛函薛定谔图中，我们用变分波泛函描述了扩展量子场的动力学。对于自由场，变分波泛函采用广义高斯形式。我们构造了由变分原理导出的运动方程的变解中的升压族。