基于一个考虑相变的流体动力学模型,对近年来的高能重离子碰撞实验进行了数值分析,讨论了QGP流体初始状态随碰撞核质量的系统变化.在前一篇文章中,我们建立了一个具有相变的夸克-胶子等离子体的(3+1)维流体动力学模型,并对时空演化进行了详细的数值讨论。本文将数值解与CERN WA 80和NA 35给出的强子分布进行了比较。通过对各种碰撞核实验的系统分析,讨论了流体动力学模型的初始参数对碰撞核质量的依赖关系。此外,我们还外推了150 GeV/A铅-铅碰撞的强子分布。
英文摘要:
We numerically analyze recent high energy heavy-ion collision experiments based on a hydrodynamical model with phase transition and discuss a systematic change of initial state of QGP-fluid depending on colliding-nuclei's mass. In a previous paper, we formulated a (3+1)-dimensional hydrodynamical model for quark-gluon plasma with phase transition and discussed numerically the space-time evolution in detail. We here compare the numerical solution with the hadronic distributions given by CERN WA80 and NA35. Systematic analyses of the experiments with various colliding nuclei enable us to discuss the dependences of the initial parameters of the hydrodynamical model on colliding nuclei's mass. Furthermore, extrapolating the present experiments, we derive the possible hadronic distributions for lead-lead 150GeV/A collision.
Effect of viscosity on one dimensional hydrodynamic flow and direct photons from 200 AGeV S+Au collisions at CERN SPS
我们在一维流体动力学模型中分析了CERN SPS上WA 80合作在200 A GeV S + Au碰撞中获得的直接光子数据。考虑了两种情况:(i)形成夸克-胶子等离子体和(ii)形成热强子气体。对于这两种情况,考虑了理想的以及极端粘性的流体。结果表明,无论流体是理想流体还是极端粘性流体,对QGP的直接光子产额影响不大。然而,如果产生强子气体,产率则有很大的不同。这两种情况都没有对数据作出令人满意的描述。
Hydrodynamical Description of 200 A GeV/c S+Au Collisions: Hadron and Electromagnetic Spectra
我们用流体动力学方法研究了200 A GeV/c的相对论S+Au碰撞。我们测试各种状态方程(EOSs),这是用来描述强相互作用的物质在CERN-SPS重离子实验中达到的密度。对于每个状态方程,可以确定合适的初始条件来重现实验强子谱;这强调了在这种方法中初始条件和状态方程之间的模糊性。同时计算了热光子谱和双电子谱,并与实验结果进行了比较。如果允许随着温度升高而激发共振态,则来自具有和不具有相变的情况的电磁信号非常相似,并且在当前实验分辨率内不可分辨。关于CERES双轻子数据,没有一个EOSs与标准的首阶双轻子速率一起被考虑,成功地再现了所观察到的低于ρ峰的过量双轻子。然而,我们的工作表明,改进的光子和双轻子光谱测量有可能强烈约束状态方程。
Comparison of space-time evolutions of hot/dense matter in $\sqrt{s_{NN}}$=17 and 130 GeV relativistic heavy ion collisions based on a hydrodynamical model
Dynamical freeze-out criterion in a hydrodynamical description of Au + Au collisions at $\sqrt{s_\mathrm{NN}}=200$ GeV and Pb + Pb collisions at $\sqrt{s_\mathrm{NN}}=2760$ GeV
Pion and Strangeness Production as Signals of QCD Phase Transition
结果表明,在15 A GeV/c(BNL AGS)和160 A GeV/c(CERN SPS)碰撞能量范围内,中心核-核碰撞中π介子和奇异态的产生与形成夸克-胶子等离子体的假设是一致的.在统计方法的框架下解释的实验结果表明,在相变过程中,有效自由度增加了约3倍,并且在CERN SPS能量下产生的等离子体可能具有约280 MeV的温度(能量密度$\approx$ 10 GeV/fm^3)。为了局域化阈能和研究QCD相变的性质,迫切需要在20-160 A GeV/c能量范围内对中心Pb+Pb碰撞进行实验研究。
Thermalization component model of multiplicity distributions of charged hadrons at BNL($E^{lab}_{NN}=2-11.6GeV/c$), the CERN($E^{lab}_{NN}=20-200GeV/c$), and the BNL ($\sqrt{s_{NN}}=19.6-200 GeV$)
Even-by-event hydrodynamical simulations for $\sqrt{s}_{NN}$=200 GeV Au+Au collisions and the correlation between flow coefficients and initial asymmetry measures
Baryon productions and collective flow of relativistic heavy-ion collisions in the AGS, SPS, RHIC and LHC energy regions($\sqrt{s_{NN}}\leq5$GeV to 5.5 TeV)