Im or Perfect Fluidity vs Initial Conditions

1
(Im) or Perfect Fluidity vs Initial Conditions
And Non-equilibrium Physics in AA
(or Splashing some cold water on our perfect
fluid)

• Hydro interpretation of v2(pT)
• report on (T.Hirano, Y. Nara, A.Dumitru, H.
  Dresher) work
• Hydro interpretation of C2(Df ptrig, passoc)
• report on (H.Casalderrey-Solana,D.Teaney)
  and (B.Betz etal)
• Need independent hard probes to constrain IC and
  NeP

Miklaz Gyulassy, FIAS/Columbia, April 18, 2007
2
Azimuthal Dependence of Radial Flow Elliptic Flow
Ollitrault (92)?
T.Hirano 2007
How does the system respond to spatial anisotropy?
Collective or Hydro behavior
No secondary interaction
y
?
x
Initial Conditions
Spatial Anisotropy
2v2
Interaction among produced particles
Freeze-Out
dN/d?
dN/d?
Momentum Anisotropy
?
0
2?
?
0
2?
3
Time Evolution of a QGP Fluid
THGyulassy(06)?
QGP
mixed
hadron
Anisotropy of energy density distribution ?
Anisotropy of Momentum distribution
4
Elliptic Flow --Centrality Dependence--
T.Hirano, Y.Nara, et al.(06)?
Fluid Ideal hydrodynamics Gas Boltzmann equation

• QGP hadron fluids
• Overshoot at large impact
• parameter
• QGP fluid and hadron gas
• Reasonable reproduction
• Caveat fluctuation effects
• Hadron gas (Courtesy of M.Isse)?
• Undershoot at any impact
• parameters

Impossible to interpret data from hadronic
degree of freedom only.
Large ? Impact parameter ? Small
5
Elliptic Flow --Wave Length Dependence--
THirano et al.(in preparation)?
All results are from QGP fluid hadron gas picture

• A QGP fluid hadron gas
• picture at work
• Particle-species
• dependence O.K. for
• pi mesons, K mesons
• and protons.
• Break down in
• short wave length region.

Long ? Wave length ? Short
6
Is mass ordering for v2(pT) a signal of the
perfect QGP fluid?
Pion
20-30
Proton
Mass ordering comes from rescattering effect.
Interplay btw. radial and elliptic flows ?Not a
direct sign of the perfect QGP fluid
Mass dependence is o.k. from hydrocascade.
First Slash of Cold Water
7
Why Perfect QGP Fluid Core Hadron Gas Corona
May Reproduce Data?
? shear viscosity, s entropy density
TH and Gyulassy (05)?
Kovtun,Son,Starinets(05)?

• Absolute value of viscosity

• Its ratio to entropy density

!
Rapid increase of entropy density near Tc could
validate hydro at RHIC/LHC Deconfinement Signal ?!
8
A Much Colder Splash on Perfect Fluidity
Challenging Results with CGC Initial
Conditions Perfect QGP Fluid Lousy Hadron
Gas
The Attack of the Color Condensers Mafia A.
Dumitru and Gang (Nara, Drescher)
9
v2(Npart) from CGC QGP Fluid Hadronic Gas
Model
T.Hirano et al. Phys.Lett.B636299-304,2006

• Glauber
• Early thermalization
• Discovery of Perfect Fluid QGP
• CGC
• Imperfect fluid !
• Normal QCD viscosity in QGP ??

Critical to understand initial conditions much
better for making a conclusion
Adil, Gyulassy, Hirano PRD73074006, (06)?
10
The Culprit Large Eccentricity from CGC Initial
Condition
y
x
Hirano and Nara(04), Hirano et al.(06)? Kuhlman
et al.(06), Drescher et al.(06)?
Pocket formula (ideal hydro) v2 0.2? _at_ RHIC
Ollitrault(92)?
11
v2(?) _at_ LHC and v2(sqrt(sNN))?

• v2 monotonically increases in the hybrid model.
• Hadronic dissipation washes out a bump predicted
  at low energies.

• Total v2 generated mainly
• in the QGP phase but .

More Cold Water
Teaney et al.(02)?
12
Conclusions IF Glauber IC are right

• Perfect fluid QGP core Dissipative hadronic
  corona at work in heavy ion collisions
• Perfect fluidity of the QGP is needed to gain
  enough elliptic flow.
• Dissipation (finite mean free path) for hadrons
  is also important.
• Indication of deconfinement transition???

13
Conclusion (contd.)?
Conclusions IF CGC IC are right

• Fragility of agreement btw. hydro and data proven
  by Hirano et al. This is central challenge to
  RHIC/LHC physics!
• CGC I.C. generates too much initial eccentric
  profile in the transverse plane.
• QGP AdS/CFT but rather QGP wQGP
• Critical to understanding initial conditions
  better
• Maybe the CGC Model is Wrong and Glauberian IC is
  closer to Nature !! (This is what I think)

???
We still have a lifeboat
14
Part II To Mach or Not

• Jet Quenching is main new dynamic QCD phenomenon
  at RHIC and soon LHC
• Single hadron observables reveal high opacity
  with dNg/dy 1000 , e 100 eNuke
• Di and Tri Hadron associated correlations
• Test coupling dynamics to sQGP matter
• Recent RHIC data reveal highly nontrivial
  phenomena
• That may test Jet-Bulk Hydro coupling IF we knew
• Better the Jet Source Initial Conditions

15
QM06 STAR prelim Jet correlation data Hydro
Mach Cones? or Radiative Dead Cone Loss? or is
exp ZYAM to blame ? ?
Zero Yield At Minimum Assumption
16
Im and Perfect Fluid Hydro Modes
Jorge Casalderrey-Solana QM06
Diffuson (Rµ)
Not propagating mode
Remembers source direction
NR fluid dynamics ?
The strength of the two modes is set by the shape
of the bullet
What sets relative mode amplitude in Jet-Medium
interaction?
17
Associated Spectrum
The fluid picture is not directly observed
Spectrum Cooper-Fry
passocT
fluid cell velocity
For passocTgtgtT angular distribution Peaks at
passocT vflow but only broad angle
distribution at low pT T
Peaks at back jet direction
No large angle correlation at small passocT
Only High passocTgtgtT particles reflect the Mach
flow
Jorge Casalderrey-Solana QM06
18
Jet- Fluid Coupling Mechanisms
Jet En-Mom Source for associated hydro evolution
Depostion/thermaliztion process
An integral constraint on Jm
The source is not unique and depends on
non-equilibrium transport dynamics outside hydro
framework
ANY Function with zero integral !

Scenario 1
Scenario 2
Non-isentropic excitations the main excitation
mechanism is entropy production and the flow
field introduces vorticity.
Isentropic excitations No entropy production.
Medium excitation by sound wave emission..
Jorge Casalderrey-Solana QM06
19
Two IC Source Scenarios of CST
? (fm)
? (fm)
x (fm)
x (fm)
Isentropic excitations No significant entropy
production. Medium excitation by sound wave
emission.
Non isentropic excitations the main excitation
mechanism is entropy production and the flow
field introduces vorticity.
20
The Non Isentropic Scenario gives No Mach after
Cooper-Frying
dN/dydDf
Diffuson ? flow along jet direction
No Mach angle correlation
p
Df
Chaudhuri Heinz No luck either with their IC
guesses
This most natural Jet source pushes more fluid
matter forward than to the side! A bummer.
21
Scenario II Isentropic Jet Source
Can be engineered to produce a Mach-like Dip At
Dfp for high pt associated similar to data
22
Jet Shock Heating vs Pebble Dropping
(see also B. Betz talk)
Scenario 3
Scenario 4
1 Fluid Jet Shock Medium
Pebbles Dr1.6 fm dropped in Medium
Engineered Mach Cone
(T0338 MeV)
Frankfurt Hydro Club B. Betz, G. Torrieri, E.
Molnar , , MG
Both scenarios look promising for Jet Mach Cone
candidates
23
Entropy Producing Jet shock heating
Jet pebbles dropped into sQGP pond
Pre-Cooper-Frye
Pre-Cooper-Frye
1/cs
p40
p40
Cooper-Fryed
Cooper-Fryed
30
30
20
No hint Of Mach!
Mach-ish But not 1/cs
Cos q
Cos q
24
Jet -gt Hadron Mach cones depend sensitively on
microscopic En-Mom deposition dynamicsoutside
the domain of hydrodynamics
Conclusions Part II

• Typical pQCD radiation dynamics H-gt Hg
• do not lead to isentropic hydro source but leads
• To dead cones instead.
• AdS/CFT string drag Mach-ish dTmn(x)
• have not been yet tested through
  Cooper-Frying
• I expect that near zone non-linear grav
  interaction
• produce an eff source that overwhelms signal
  from weak Mach sound similar to Jet shocks

25
Heavy Quarks in TOE
You are here
Gubser
Myers
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(MQ Infinity)
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(No Transcript)
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(from the AdS5 Black Hole)
Kovtuns conclusions
Could it be that the AdS/CFT is not applicable at
RHIC because of unfavorable initial conditions
in AA ??