Shoji Hirano Shusaku Tsumoto hirano@ieee tsumoto@computer Dept of Medical Informatics,
Theoretical Overview Tetsufumi Hirano Department of Physics The University of Tokyo Homepage of...
Transcript of Theoretical Overview Tetsufumi Hirano Department of Physics The University of Tokyo Homepage of...
Theoretical Overview
Tetsufumi HiranoDepartment of PhysicsThe University of Tokyo
Homepage of Heavy Ion Caféhttp://tkynt2.phys.s.u-tokyo.ac.jp/~hirano/hic/index.html
--Current status of “perfect liquid”--
Outline
My personal view of “Perfect Liquid announcement” and QM2006
What’s Next?Systematic study based on the hybrid appro
ach (base line argument) Initial condition & mechanism of thermalizati
on Improvement of current hydro modelsUtilizing outputs from hydro simulations
Elliptic Flow for Charged Particles
T.H.(’01)
P.Huovinen(’03)Roughly speaking,ideal hydro gives a good description
Roughly speaking,ideal hydro gives a good description
P.Kolb et al.(’01)
TH, plenary talk @ QM2004
I did not make a conclusive statement @ QM2005
TH, plenary talk @ QM2004
An announcement was made on April 18, 2005
Behind the Press Release Room…
Today, I won’t discuss this particular topic any more.See, TH and M.Gyulassy, NPA769,71(2006).
TH, talk @ APS meeting, FL, 2005
Nothing about “press release” nor “perfect liquid”
Mystery at QM2005, Budapest (Just 4 Months after Press Release)
8 plenary talks from RHICBRAHMS(1 talk), PHENIX(3 talks),PHOBOS(1 talk), STAR(3 talks).
What happened to the press release on “perfect fluidity”?
The press release was just a dream?Two Logos (perfect liquid, sQGP) are enough?
TH, talk @ BNL, 11/04/2005
QM2006 @ Shanghai
24 plenary theory speakers+52 parallel theory speakers
(Impossible to cover all of them…)Who cares about “perfect fluid”
in this conference?
What’s Next ?
1. Systematic studies based on1. Systematic studies based onthe hybrid approachthe hybrid approach
(Glauber I.C. + perfect fluid QGP + dissipative hadron gas). HBT, source functions
System size, collision energy
2. Initial condition & mechanism2. Initial condition & mechanism of early thermalizationof early thermalization
CGC, ”Glasma” Isotropization
Instability Non-equilibrium field theory
3. Improvement of current 3. Improvement of current hydro modelshydro models
Fluctuations Constraint of EOS (Causal) Viscosity
Chemical non-equilibriumMach cone
4. Utilizing outputs from 4. Utilizing outputs from hydrodynamic simulationshydrodynamic simulations
Jet quenching (q, Q, and g) J/ transport
E&M radiation Recombination
TH, a slide prepared for YKIS06
•3D Langrangean hydro + UrQMD + Jet Quenching +…C.Nonaka(plenary), S.Bass(parallel),…•3D Eulerian Hydro + JAM + Jet Quenching +…TH(parallel), (Y.Nara),M.Isse(poster),…
1. Systematic studies based on1. Systematic studies based onthe hybrid approachthe hybrid approach
(Glauber I.C. + perfect fluid QGP + dissipative hadron gas). HBT, source functions
System size, collision energy
Current Status of Hydro+Cascade
0z
t
QGP fluid
hadronic gas
Perfect fluid QGP coreDissipative hadronic coronaTH and M.Gyulassy (2006)
Inputs of the Model
SolverFull 3D Eulerian ideal hydro + JAMInitial ConditionInitial time 0: 0.6fm/cTransverse profile: 0.85part+0.15coll
Longitudinal profile: BGK triangle (Brodsky-Gunion-Kuhn)EoSNf=3 massless ideal QGP gas+Resonance gas (up to (1232))in partial chemical equilibriumCritical temperature Tc: 170MeVChemical f.o. temperature Tch: 170MeVSwitching temperature Tsw: 169MeV
pT Spectra from QGP Fluid
+ Hadron Gas Model
A hybrid model works well up to pT~1.5GeV/c.Other components (reco/frag) would appear above.
Elliptic Flow from QGP Fluid + Hadron Gas Model
Good agreement for bulk (pT<~1.5GeV/c)
PID v2(pT) at midrapidity
O.K. in semicentral collisions
Presumably due to fluctuationMiller&Snellings(’03)
Hydro + cascade at work in forward
Adapted from S.J.Sanders (BRAHMS) @ QM2006
A Probable Scenario TH and Gyulassy (’06)
!•Absolute value of viscosity •Its ratio to entropy density
Rapid increase of entropy density canmake hydro work at RHIC.
Deconfinement Signal?!
: shear viscosity, s : entropy density
Kovtun,Son,Starinets(’05)Kovtun,Son,Starinets(’05)
Other systems?Kapusta, talk @ QM2006Csernai,Kapusta, McLerran(’06)
Something happens at TcNot driven by entropy jump…
2. Initial condition & mechanism2. Initial condition & mechanism of early thermalizationof early thermalization
CGC, ”Glasma” Isotropization
Instability Non-equilibrium field theory
Plenary•F.Gelis, QCD at small x•M.Strickland, Thermalization via instabilitiesParallel•R.Venugopalan, Multiple production to NLO in AA collisions•M.Asakawa, Anomalous viscosity of an expanding quark-gluon plasma•R.Fries, Early time evolution of high energy heavy ion collisions•Z.Xu, Parton Thermalization and Energy Loss in U.R.H.I.C within a P.C.•X.-M.Xu, Thermalization of Quark-Gluon Matter
How Do Partons Get Longitudinal Momentum to Thermalize?
Free Streaming eta=y
dN/dy
y=
dN/dy
y≈Sum of delta function Width “Thermal” fluctuation
Sheet:eta=const
22 Collisions Do Not Help!
Xu and Greiner, hep-ph/0406278
Only 22 collisions,partons are still in atransverse sheeteta~y~const.23 may help.
Time Scale of Equilibration
0
2
2
02
2
2
2
2
2
exp)()(tt
E
pt
E
p
E
pt
E
peq
ZZeq
ZZ
(t) gives the timescale of kinetic equilibration.
Adapted from Z.Xu,Talk @ QM2006
Do we really need<pz
2>~<px2>?
Caveat on Kinetic Equilibration
Static medium ≠Expanding medium
(1+1)D Bjorken case:
Do we need complete isotropy?Shear viscosity allows small deviation fromisotropic distribution
Interplay btw. Expansion and Instability
Adapted from M.Strickland,Talk @ QM2006
Instability Adapted from M.Strickland,Talk @ QM2006
3. Improvement of current 3. Improvement of current hydro modelshydro models
Fluctuations Constraint of EOS (Causal) Viscosity
Chemical non-equilibriumMach cone
Plenary•D.T.Son, AdS/CFT and QGP•D.Teaney, Experimental evidence of perfect fluididty at RHIC•J.Kapusta, The strongly interacting low viscosity matter•J.Casalderrey-Solana, Mach Cone in QGP•P.Levai, Viscosity in the strongly interacting quark matter around Tc•C.M.Ko, Parton transport description of heavy ion collisionsParallel•T.Renk, Mach cone and dijets•G.L.Ma, Two- and Three-particle Correlations in a P.C.•S.Gavin, Measuring Shear Viscosity Using pT Correlations•S.Mrowczynski, Chromo-hydrodynamics of the unstable QGP•R.S.Bhalerao, Eccentricity fluctuations and elliptic flow at RHIC•D.Molnar, Why even a small viscosity matters at RHIC•T.Kodama, New Formulation of Dissipative Relativistic Hydrodynamics
Importance of Relaxation Time
•Non-rela. (Cattaneo (’48))
0: Fourier law
: relaxation time
Heat Eq. (Parabolic Eq.) Finite relaxation time
Telegraph Eq.(Hyperbolic Eq.)
Balance Eq.
Constitutive Eq.
Violation ofcausality
cf.)杉山勝、数理科学 (2002年8月号)
Solution of Viscous Fluids
Adapted from D.Teaney,Talk @ QM2006
Be Cautious about Corrections
Adapted from D.Teaney,Talk @ QM2006
Summary by Teaney
Adapted from D.Teaney,Talk @ QM2006
Comarison btw. Hydro and Cascade
Adapted from D.Molnar, Talk @ QM2006Many caveats in this kind of comparisons!
Boltzmann at work?
~ 15 * pert !
Caveat 1: Where is the “dilute” approximation in Boltzmannsimulation? Is ~0.1fm o.k. for the Boltzmann description?Caveat 2: Differential v2 is tricky. dv2/dpT~v2/<pT>.Difference of v2 is amplified by the difference of <pT>.Caveat 3: Hadronization/Freezeout are different.
25-30%reduction
Molnar&Gyulassy(’00) Molnar&Huovinen(’04)
gluonicgluonicfluidfluid
Schematic Picture of Shear Viscosity
See, e.g. Danielewicz&Gyulassy(’85)
Assuming relativistic particles,
Perfect fluid: 0
shear viscosity 0
Gradient of flowSmearing of flow
Next time step
A New Channel to Measure Viscosity
Adapted from S.Gavin,Talk @ QM2006
Remember shear viscosity causes diffusion of flow
Correlation is broadened
Correlation fn. of pT
Adapted from S.Gavin, Talk @ QM2006
Turbulent Leads Perfect Fluid?
Adapted from M.Asakawa, Talk @ QM2006
Anomalously “Small” Viscosity
Adapted from M.Asakawa, Talk @ QM2006
“Mach Angle”
Adapted from J. Casalderrey-Solana, Talk @ QM2006
Mach “Emission” Angle Sound Velocity
Adapted from H.Stöcker, Talk @ Xi’an workshop
Dissipation Destroys Mach Cone?
Following figures taken from a talk by StöckerViscous hydro simulations by Brazil groupSee also, T.Kodama, talk @QM2006
Mach “Emission” Angle~80 Deg.?
Adapted from H.Stöcker, Talk @ Xi’an workshop
Current Data Consistent with Soft EoS (on average)!?
Adapted from H.Stöcker, Talk @ Xi’an workshop
3-Particle Correlation
Adapted from G.-L. Ma, Talk @ QM2006
Mach Cone in AMPT?
Adapted from G.-L. Ma, Talk @ QM2006
Hadronic Rescattering is not enough?
Adapted from G.-L. Ma, Talk @ QM2006Caveat: AMPT does not reproduce RAA
4. Utilizing outputs from 4. Utilizing outputs from hydrodynamic simulationshydrodynamic simulations
Jet quenching (q, Q, and g) J/ transport
E&M radiation Recombination
Plenary•P.F.Zhuang, J/ suppression and regenerationParallel•J.-e Alam, Thermal Radiation at RHIC•S.Turbide, High Momentum Dilepton Production From Jets in a QGP•J.Long, Photons and Evolution of chemically equilibrating and expanding QGP at finite baryon densityPoster•M.Isse, Jet-fluid string formation and decay in high energy H.I.C.
J/ transport in QGP fluids
Adapted from P.F.Zhuang,Talk @ QM2006
2+1D Boltzmann+suppression +regeneration
J/ transport in QGP fluids (contd.)
Adapted from P.F.Zhuang,Talk @ QM2006
RAA for J/
Adapted from P.F.Zhuang,Talk @ QM2006
Hydro Data Available
http://tkynt2.phys.s.u-tokyo.ac.jp/~hirano/parevo/parevo.html
Summary
Agreement btw. “hydro+cascade” and data indicates “Perfect Liquid”.
It is worth following up the analysis.Important to understand initial conditions.Viscous hydro as an applicable conditionConsistency among models Utilize th
e hydro data.
What’s Next ?
1. Systematic studies based on1. Systematic studies based onthe hybrid approachthe hybrid approach
(Glauber I.C. + perfect fluid QGP + dissipative hadron gas). HBT, source functions
System size, collision energy
2. Initial condition & mechanism2. Initial condition & mechanism of early thermalizationof early thermalization
CGC, ”Glasma” Isotropization
Instability Non-equilibrium field theory
3. Improvement of current 3. Improvement of current hydro modelshydro models
Fluctuations Constraint of EOS (Causal) Viscosity
Chemical non-equilibriumMach cone
4. Utilizing outputs from 4. Utilizing outputs from hydrodynamic simulationshydrodynamic simulations
Jet quenching (q, Q, and g) J/ transport
E&M radiation Recombination
BGK triangle
Adapted from A.Adil,Talk @ QM2006
Two-Particle Correlation Function
hydro, blast-wave,hydro, blast-wave,cascade, …cascade, …
relative distance dist.pair wave fn.(FSI? Coulomb?)
normalized source fn.
C2
fitting?
Source Function from 3D Hydro + Cascade
Blink: Ideal Hydro, Kolb and Heinz (2003)Caveat: No resonance decays in ideal hydro
How much the source function differs from ideal hydro in Configuration space?
Non-Gaussian Source?
x
y
px=0.5GeV/c