# Quark Matter 2012

12-18 August 2012
US/Eastern timezone

## Event-by-event distribution of azimuthal asymmetries in ultrarelativistic heavy-ion collisions

16 Aug 2012, 16:00
2h
Regency 1/3 and Ambassador ()

### Regency 1/3 and Ambassador

Poster Global and collective dynamics

### Speaker

Dr Harri Niemi (University of Jyväskylä, Department of Physics)

### Description

Nowadays, relativistic dissipative fluid dynamics is a common tool to describe the space-time evolution of the quark-gluon plasma (QGP) created in ultrarelativistic heavy-ion collisions. The validity of the fluid-dynamical approach is experimentally confirmed by the fact that initial-state anisotropies are directly converted into nonvanishing (event-averaged) Fourier coefficients $\langle v_n \rangle$ of the decomposition of the single-inclusive momentum distribution of hadrons with respect to the azimuthal angle. From the magnitude of the $\langle v_n \rangle$ one can obtain information about the size of dissipative corrections and thus infer the value of the viscous coefficients of the QGP. It has been realized that, for a proper comparison to experimental data and a reliable extraction of viscosity, fluid-dynamical calculations have to be performed on an event-by-event basis. Therefore, fluid dynamics should not only be able to predict the correct event-averaged $\langle v_n\rangle$, but also their distributions. In this paper, we investigate the event-by-event distribution of the initial-state eccentricities $\varepsilon_n$, and show how they correlate with the event-by-event distribution of the Fourier coefficients $v_n$. In order to generate the initial state, we use the Monte-Carlo Glauber model of Ref.\ [1]. For the fluid-dynamical evolution, we use the model of Refs.\ [2]. The final hadron spectra are calculated with the Cooper-Frye freeze-out procedure. We demonstrate that the event-by-event distributions of the $v_n$, and not only their average values, are promising observables to gain information about the initial state of the fluid-dynamical evolution and the transport properties of the hot and dense, strongly interacting matter created in heavy-ion collisions. [1] H.~Holopainen, H.~Niemi, and K.~J.~Eskola, Phys.\ Rev.\ {\bf C83}, 034901 (2011), [arXiv:1007.0368 [hep-ph]]. [2] H.~Niemi, G.~S.~Denicol, P.~Huovinen, E.~Molnar, and D.~H.~Rischke, Phys.\ Rev.\ Lett.\ {\bf 106}, 212302 (2011), [arXiv:1101.2442 [nucl-th]]; H.~Niemi, G.~S.~Denicol, P.~Huovinen, E.~Molnar and D.~H.~Rischke, arXiv:1203.2452 [nucl-th].

### Primary author

Dr Harri Niemi (University of Jyväskylä, Department of Physics)

### Co-authors

Dirk Rischke (University Frankfurt) Dr Etele Molnar (MTA Wigner Research Centre for Physics) Gabriel Denicol (Frankfurt University) Hannu Holopainen (Frankfurt Institute for Advanced Studies) Pasi Huovinen (Johann Wolfgang Goethe-Universität)

### Presentation Materials

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