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Dynamics of the quark-gluon plasma and high density hadronic matter

夸克-胶子等离子体和高密度强子物质的动力学

基本信息

批准号：
14540255
负责人：
ASAKAWA Masayuki
金额：
$ 1.73万
依托单位：
Osaka University (2004)Kyoto University (2002-2003)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14540255/
关键词：
lattice gauge theory spectral function high energy heavy ion collision universality phase transition fluctuation equation of state finite temperature field theory 超相対論的重イオン衝突非平衡場の理論カイラル対称性超相対論点重イオン衝突

项目摘要

1 We have constructed the spectral functions at finite temperature for the vector (J/ψ) and axial-vector (η_c) channels made of a charm and anti-charm quark pair from their correlation functions measured on the Euclidean lattices with the maximum entropy method, which was applied systematically to lattice gauge theory for the first time by our group. It was shown that both states continue to exist up to a temperature that is much higher than the QCD phase transition temperature, that is, about 1.6T_c and that they both disappears in a very narrow temperature region, between about 1.6T_c and 1.7T_c This suggests that the quark-gluon plasma is not a state where quarks and gluons are almost freely moving as usually believed, but that it is a strongly coupled system where also hadronic excitations coexists.2 It has been argued that there is possibly a critical end point on the QCD phase diagram, where the order of the phase transition changes from first to crossover We have derived general equations of states with a critical end point on the basis of the universality hypothesis in phase transition theory and found that it acts as an attractor in the course of the time evolution of the system. Furthermore, we discussed for the first time the time evolution of fluctuations and correlation lengths when the system created in high energy heavy ion collisions pass the proximity of the critical end point in the course of its time evolution and their effects on observables in a unified framework.

1 我们利用最大熵法在欧氏晶格上测得的相关函数，构建了粲夸克对和反粲夸克对构成的矢量（J/ψ）和轴矢量（η_c）通道在有限温度下的谱函数，该方法首次系统地应用于晶格规范理论。结果表明，这两种状态在远高于 QCD 相变温度的温度（即约 1.6T_c）下都继续存在，并且它们都在非常窄的温度区域（约 1.6T_c 和 1.7T_c 之间）中消失。这表明夸克-胶子等离子体并不是通常认为的夸克和胶子几乎自由移动的状态，而是一个强耦合系统，其中也存在强子激发 2 有人认为，QCD 相图上可能存在一个临界终点，相变的顺序从最初变为交叉。我们根据相变理论中的普遍性假设推导了具有临界终点的一般状态方程，并发现它在系统时间演化过程中充当了吸引子的作用。此外，我们首次在统一的框架中讨论了高能重离子碰撞中产生的系统在其时间演化过程中经过临界终点附近时波动和相关长度的时间演化及其对可观测值的影响。