Transcript スライド 1 - University of Tokyo

AM and T. Hirano, Phys. Lett. B 703, 583 (2011)
Viscous Hydrodynamic Deformation in Rapidity
Distributions of the Color Glass Condensate
Akihiko Monnai
Department of Physics, The University of Tokyo
Collaborator: Tetsufumi Hirano
Workshop for Particle Correlations and Femtoscopy 2011
September 24th 2011, The University of Tokyo, Japan
Akihiko Monnai (The University of Tokyo)
Viscous Hydrodynamic Deformation in Rapidity Distribution of the Color Glass Condensate
Introduction

Quark-gluon plasma (QGP) at relativistic heavy ion collisions
Hadron phase
(crossover)
sQGP
QGP phase
RHIC experiments (2000-)
The QGP quantified as a nearly-perfect fluid
Viscosity is important in detailed analyses
LHC experiments (2010-)
Heavy ion collisions of higher energies
Will the RHIC modeling work at LHC?
WPCF 2011, Sep 24th, The University of Tokyo, Japan
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Introduction
(wQGP?)
Akihiko Monnai (The University of Tokyo)
Viscous Hydrodynamic Deformation in Rapidity Distribution of the Color Glass Condensate
Introduction

Modeling a high-energy heavy ion collision
particles
ｔ
t
Freezeout
Hadronic cascade
Hydro to particles
hadronic
phase
QGP phase
Hydrodynamic stage
Preequilibrium
z
Initial condition
Color glass condensate
Color glass condensate (CGC)
Description of saturated gluons in the nuclei before a collision (τ < 0 fm/c)
Relativistic hydrodynamics
Description of collective motion of the QGP (τ ~ 1-10 fm/c)
WPCF 2011, Sep 24th, The University of Tokyo, Japan
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The First ALICE Result
Akihiko Monnai (The University of Tokyo)
Viscous Hydrodynamic Deformation in Rapidity Distribution of the Color Glass Condensate
The First ALICE Result

Mid-rapidity multiplicity
K. Aamodt et al. PRL105 252301
Pb+Pb, 2.76 TeV at η = 0
CGC
ALICE data (most central 0-5%)
WPCF 2011, Sep 24th, The University of Tokyo, Japan
Motivation
The CGC is fit to RHIC data;
What is happening at LHC?
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CGC in Heavy Ion Collisions
Akihiko Monnai (The University of Tokyo)
Viscous Hydrodynamic Deformation in Rapidity Distribution of the Color Glass Condensate
CGC in Heavy Ion Collisions

Saturation scale in MC-KLN model
D. Kharzeev et al., NPA 730, 448
H. J. Drescher and Y. Nara, PRC 75,
034905; PRC 76, 041903
λ=0.38
Fixed via direct comparison with data
: thickness function
: momentum fraction of incident particles
λ=0.18
λ=0.28
dN/dy
dNch/dη gets steeper with increasing λ; RHIC data suggest λ~0.28
Initial conditionHydrodynamic
Observed particle
Initial condition
Observed particle
from the CGC evolution distribution distribution
from the CGC
A missing piece!
WPCF 2011, Sep 24th, The University of Tokyo, Japan
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CGC in Heavy Ion Collisions
Akihiko Monnai (The University of Tokyo)
Viscous Hydrodynamic Deformation in Rapidity Distribution of the Color Glass Condensate
CGC in Heavy Ion Collisions

CGC + Hydrodynamic Model
Initial condition
from the CGC
Hydrodynamic
evolution
Observed particle
distribution
A missing piece!
In this work…
We estimate hydrodynamic effects with
(i) non-boost invariant expansion
for the CGC
(ii) viscous corrections
The first time the CGC rapidity distribution is discussed in terms
of viscous hydrodynamics
WPCF 2011, Sep 24th, The University of Tokyo, Japan
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Hydrodynamic Model
Akihiko Monnai (The University of Tokyo)
Viscous Hydrodynamic Deformation in Rapidity Distribution of the Color Glass Condensate
Hydrodynamic Model

Full 2nd order viscous hydrodynamic equations
Energy-momentum conservation
+
AM and T. Hirano, NPA 847, 283
EoM for bulk pressure
EoM for shear tensor
All the terms are kept
Solve in (1+1)-D relativistic coordinates (= no transverse flow)
with Landau frame where local energy flux is the flow
WPCF 2011, Sep 24th, The University of Tokyo, Japan
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Model Input for Hydro
Akihiko Monnai (The University of Tokyo)
Viscous Hydrodynamic Deformation in Rapidity Distribution of the Color Glass Condensate
Model Input for Hydro

Equation of state and transport coefficients
Equation of State:
Lattice QCD
S. Borsanyi et al., JHEP 1011, 077
Shear viscosity:
η = s/4π
Bulk viscosity:
ζeff = (5/2)[(1/3) – cs2]η
P. Kovtun et al., PRL 94, 111601
A. Hosoya et al., AP 154, 229
Relaxation times:
Kinetic theory
2nd order coefficients: Kinetic theory

AM and T. Hirano, NPA 847, 283
Boundary conditions at the initial time
Initial flow:
Bjorken flow (i.e. flow rapidity Yf = ηs)
Energy distribution: MC-KLN type CGC (averaged over transverse area)
Dissipative currents:
WPCF 2011, Sep 24th, The University of Tokyo, Japan
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Results
Akihiko Monnai (The University of Tokyo)
Viscous Hydrodynamic Deformation in Rapidity Distribution of the Color Glass Condensate
Results

Distributions at isothermal hypersurface Tf = 0.16 TeV
LHC
RHIC
Outward entropy flux
Entropy production
Flattening
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
WPCF 2011, Sep 24th, The University of Tokyo, Japan
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Results
Akihiko Monnai (The University of Tokyo)
Viscous Hydrodynamic Deformation in Rapidity Distribution of the Color Glass Condensate
Results

Hydrodynamic parameter dependences (at the LHC)
Entropy production is roughly proportional to viscous coefficients
Shear viscous effects are dominant in the QGP phase

CGC parameter dependence to be explored
Fix the real λ from rapidity distribution and centrality dependences
WPCF 2011, Sep 24th, The University of Tokyo, Japan
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Summary and Outlook
Akihiko Monnai (The University of Tokyo)
Viscous Hydrodynamic Deformation in Rapidity Distribution of the Color Glass Condensate
Summary and Outlook

We solved full 2nd order viscous hydro in (1+1)-dimensions
for the “shattered” color glass condensate
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

Future prospect includes:
AM & T. Hirano, in preparation
– Analyses on the CGC parameter dependences, rcBK, etc…
– Estimation of the effects of transverse flow via developing
(3+1)-dimensional viscous hydrodynamic model, etc…
WPCF 2011, Sep 24th, The University of Tokyo, Japan
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The End
Akihiko Monnai (The University of Tokyo)
Viscous Hydrodynamic Deformation in Rapidity Distribution of the Color Glass Condensate
The End
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
Thank you for listening!
Website: http://tkynt2.phys.s.u-tokyo.ac.jp/~monnai/index.html
WPCF 2011, Sep 24th, The University of Tokyo, Japan
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