Speaker
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We 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 $\eta/s$ by mean of an event-by-event transport approach. We study the effect of the $\eta/s$ ratio on the build up of the $v_n(p_T)$. In particular we study the effect of a temperature dependent $\eta/s$ 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. In ultra-central collisions the $v_n(p_T)$ show a strong sensitivity to the $\eta/s$ ratio in the QGP phase and this sensitivity increase with the increase
of the order of the harmonic. Moreover, we discuss the correlation between the initial spatial anisotropies $\epsilon_n$ and flow coefficients $v_n$. We find that at LHC energies the $v_n$ are more correlated to the initial $\epsilon_n$ respect to RHIC energies.
We find that the elliptic flow $v_2$ is strongly correlated with initial eccentricity $\epsilon_2$. While higher harmonics $v_3$, $v_4$ and $v_5$ are weakly correlated to their asymmetry measure in coordinate space $\epsilon_3$, $\epsilon_4$ and $\epsilon_5$. The degree of correlation increase with the impact parameter. At LHC energies and in ultra-central collisions we find that the linear correlation coefficent $C(n,n) \approx 1$ for $n=2,3,4$ and $5$.
