akihiko monnai department of physics, the university of tokyo collaborator: tetsufumi hirano v...

Akihiko MonnaiDepartment of Physics, The University of Tokyo

Collaborator: Tetsufumi Hirano

Viscous Hydrodynamic Deformation in Rapidity Distributions of the Color Glass Condensate

Workshop for Particle Correlations and Femtoscopy 2011September 24th 2011, The University of Tokyo, Japan

AM and T. Hirano, Phys. Lett. B 703, 583 (2011)

WPCF 2011, Sep 24th, The University of Tokyo, Japan

Akihiko Monnai (The University of Tokyo) Viscous Hydrodynamic Deformation in Rapidity Distribution of the Color Glass Condensate

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Introduction Quark-gluon plasma (QGP) at relativistic heavy ion collisions

Hadron phase QGP phase

　(crossover) sQGP (wQGP?)

The QGP quantified as a nearly-perfect fluid

RHIC experiments (2000-)

Viscosity is important in detailed analyses

Introduction

LHC experiments (2010-)

Heavy ion collisions of higher energies

Will the RHIC modeling work at LHC?



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Introduction Modeling a high-energy heavy ion collision

The First ALICE Result

particles

hadronic phase

QGP phase

Freezeout

Pre-equilibrium

Hydrodynamic stage

Color glass condensate

Hadronic cascade

Initial condition

Hydro to particles

ｔ

z

t

Color glass condensate (CGC)

Relativistic hydrodynamics

Description of saturated gluons in the nuclei before a collision (τ < 0 fm/c)

Description of collective motion of the QGP (τ ~ 1-10 fm/c)



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The First ALICE Result Mid-rapidity multiplicity

CGC in Heavy Ion Collisions

ALICE data (most central 0-5%)

CGC

Pb+Pb, 2.76 TeV at η = 0

K. Aamodt et al. PRL105 252301

MotivationThe CGC is fit to RHIC data; What is happening at LHC?



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CGC in Heavy Ion Collisions Saturation scale in MC-KLN model

CGC in Heavy Ion Collisions

Fixed via direct comparison with data

dNch/dη gets steeper with increasing λ; RHIC data suggest λ~0.28

Initial conditionfrom the CGC

Hydrodynamic evolution

Observed particle distribution

A missing piece!



: thickness function: momentum fraction of incident particles

D. Kharzeev et al., NPA 730, 448H. J. Drescher and Y. Nara, PRC 75, 034905; PRC 76, 041903

dN/dy

λ=0.28λ=0.18

λ=0.38



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CGC in Heavy Ion Collisions CGC + Hydrodynamic Model

Hydrodynamic Model


Hydrodynamic evolution


A missing piece!

The first time the CGC rapidity distribution is discussed in terms of viscous hydrodynamics

We estimate hydrodynamic effects with(i) non-boost invariant expansion(ii) viscous corrections

for the CGC

In this work…



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Hydrodynamic Model Full 2nd order viscous hydrodynamic equations

Model Input for Hydro

Solve in (1+1)-D relativistic coordinates (= no transverse flow) with Landau frame where local energy flux is the flow

EoM for bulk pressure

EoM for shear tensor

Energy-momentum conservation +AM and T. Hirano, NPA 847, 283

All the terms are kept



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Model Input for Hydro Equation of state and transport coefficients

Boundary conditions at the initial time

Results

Equation of State: Lattice QCD

Shear viscosity: η = s/4π

2nd order coefficients: Kinetic theory

Initial flow: Bjorken flow (i.e. flow rapidity Yf = ηs)

Bulk viscosity: ζeff = (5/2)[(1/3) – cs2]η

Relaxation times: Kinetic theory

S. Borsanyi et al., JHEP 1011, 077

P. Kovtun et al., PRL 94, 111601A. Hosoya et al., AP 154, 229

AM and T. Hirano, NPA 847, 283

Energy distribution: MC-KLN type CGC (averaged over transverse area)

Dissipative currents:



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Results Distributions at isothermal hypersurface Tf = 0.16 TeV

Results

Outward entropy flux FlatteningEntropy production Enhancement

If the true λ is larger at RHIC, it enhances dN/dy at LHC;Hydro effect is a candidate for explaining the “gap” at LHC

RHIC LHC



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Results Hydrodynamic parameter dependences (at the LHC)

CGC parameter dependence to be explored

Summary and Outlook

Entropy production is roughly proportional to viscous coefficients Shear viscous effects are dominant in the QGP phase

Fix the real λ from rapidity distribution and centrality dependences



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Summary and Outlook We solved full 2nd order viscous hydro in (1+1)-dimensions

for the “shattered” color glass condensate

Future prospect includes:– Analyses on the CGC parameter dependences, rcBK, etc…– Estimation of the effects of transverse flow via developing

(3+1)-dimensional viscous hydrodynamic model, etc…

The End

AM & T. Hirano, in preparation

Non-trivial deformation of CGC rapidity distribution due to(i) outward entropy flux (non-boost invariant effect)

(ii) entropy production (viscous effect)

Viscous hydrodynamic effect may play an important role in understanding the seemingly large multiplicity at LHC



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The End Thank you for listening! Website: http://tkynt2.phys.s.u-tokyo.ac.jp/~monnai/index.html

http://tkynt2.phys.s.u-tokyo.ac.jp/~monnai/

akihiko monnai department of physics, the university of tokyo collaborator: tetsufumi hirano v...

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