Initial state fluctuations from mid-peripheral to ultra-central collisions in a event-by-event transport approach
Initial state fluctuations from mid-peripheral to ultra-central collisions in a event-by-event transport approach
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DOI：
10.1103/physrevc.92.054902
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发表时间：
2015-07
影响因子：
3.1
通讯作者：
S. Plumari;G. Guardo;F. Scardina;V. Greco
中科院分区：
文献类型：
--
作者：
S. Plumari;G. Guardo;F. Scardina;V. Greco
我们开发了一种相对论动力学输运方法，该方法结合了初始状态波动，可以研究固定$\eta/s（T）$下流体的椭圆流$v_2$和高次谐波$v_3$、$v_4$和$v_5$的建立。我们研究了$\eta/s$比及其T依赖性对两种不同束流能量的$v_n（p_T）$的建立的影响：RHIC为Au+Au在$\sqrt{s}=200 \，GeV$和LHC为$Pb+Pb$在$\sqrt{s}=2.76 \，TeV$。我们发现，对于所考虑的两种不同的光束能量，由于介质的粘性对v_n（p_T）的抑制有不同的贡献，分别来自交叉相位和QGP相位。结果表明，只有在超中心碰撞（0 - 0.2）中，vn（pT）对QGP相位中的T依赖性有较强的敏感性，且这种敏感性随谐波阶数n的增加而增加.此外，对初始空间各向异性和最终流动系数v_n之间的相关性的研究表明，在LHC能量下比在RHIC能量下有更大的相关性。从外围碰撞到中心碰撞的相关程度增加，但仅在LHC的超中心碰撞中，我们发现线性相关系数C（n，n）在n= 2，3，4 $和5 $时约为1$。这表明（$v_n$，$v_m$）空间中的最终相关性反映了（$\n$，$\n_m$）空间中的初始相关性。
We have developed a relativistic kinetic transport approach that incorporates initial state fluctuations allowing to study the build up of elliptic flow $v_2$ and high order harmonics $v_3$, $v_4$ and $v_5$ for a fluid at fixed $\eta/s(T)$. We study the effect of the $\eta/s$ ratio and its T dependence on the build up of the $v_n(p_T)$ for two different beam energies: RHIC for Au+Au at $\sqrt{s}=200 \,GeV$ and LHC for $Pb+Pb$ at $\sqrt{s}=2.76 \,TeV$. We find that for the two different beam energies considered the suppression of the $v_n(p_T)$ due to the viscosity of the medium have different contributions coming from the cross over or QGP phase. Our study reveals that only in ultra-central collisions ($0 - 0.2 \%$) the $v_n(p_T)$ have a stronger sensitivity to the T dependence of $\eta/s$ in the QGP phase and this sensitivity increases with the order of the harmonic n. Moreover, the study of the correlations between the initial spatial anisotropies $\epsilon_n$ and the final flow coefficients $v_n$ shows that at LHC energies there is more correlation than at RHIC energies. The degree of correlation increases from peripheral to central collisions, but only in ultra-central collisions at LHC, we find that the linear correlation coefficient $C(n,n) \approx 1$ for $n=2,3,4$ and $5$. This suggests that the final correlations in the ($v_n$,$v_m$) space reflect the initial correlations in the ($\epsilon_n$,$\epsilon_m$) space.