# Quark Matter 2014 - XXIV International Conference on Ultrarelativistic Nucleus-Nucleus Collisions

19-24 May 2014
Europe/Zurich timezone

## Determining QCD matter viscosity from fluid dynamics with saturated minijet initial conditions in ultrarelativistic A+A collisions

20 May 2014, 16:30
2h

### spectrum

Board: C-17
Poster Initial State Physics

### Speaker

Risto Paatelainen (University of Jyväskylä)

### Description

Using next-to-leading order perturbative QCD and a conjecture of saturation to suppress the production of low energy quanta, we calculate the initial energy densities and formation times for the dissipative fluid dynamical evolution of the quark-gluon plasma produced in ultrarelativistic heavy ion collisions [1,2]. We identify the uncertainties of the model and demonstrate the predictive power of the approach by obtaining a good global agreement with the measured centrality dependence of the charged particle multiplicities, transverse momentum spectra and elliptic flow simultaneously for the Pb+Pb collisions at the LHC and Au+Au at RHIC. In particular, the shear viscosity-to-entropy ratio in the different phases of QCD matter is simultaneously constrained by all these data. In order to study higher cumulants $v_n$ and their event-by-event (EbyE) distributions, we are currently engaged in modeling the EbyE fluctuations of saturated minijet production in this framework [3]. Also these results will be reported. [1] R. Paatelainen, K. J. Eskola, H. Holopainen and K. Tuominen, **Phys. Rev. C87** (2012) 044904 [2] R. Paatelainen, K. J. Eskola, H. Niemi and K. Tuominen, **arXiv:1310.3105** [hep-ph], to appear in **Phys. Lett. B** [3] H. Niemi, K. J. Eskola, R. Paatelainen and K. Tuominen, work in progress

### Primary authors

Harri Niemi (University of Jyväskylä) Kari J. Eskola (University of Jyvaskyla) Dr Kimmo Tuominen (University of Helsinki) Risto Paatelainen (University of Jyväskylä)

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