26-Oct-07 W.A. Zajc

Introductionand

Welcome

AdS/CFT Intersects Nuclear Beams at Columbia

W.A. ZajcColumbia University

26-Oct-07 W.A. Zajc

RHIC Perspectives

W.A. ZajcColumbia University

RHIC Perspectives

W.A. ZajcColumbia University

26-Oct-07 W.A. Zajc

Outline of My Talk

26-Oct-07 W.A. Zajc

Really, It’s A Meta-Talk

Introduction, Motivation,Definition of terms up to here

Two major discoveries:FlowJet quenching

26-Oct-07 W.A. Zajc

Really, It’s A Meta-Talk

Flow, v2 scaling with nq

26-Oct-07 W.A. Zajc

Really, It’s A Meta-Talk

Jet quenching,away-side disappearance,direct photons

Mach cones, re-appearance of the away side

26-Oct-07 W.A. Zajc

Really, It’s A Meta-Talk

Perfect liquid,KSS bound as QM resultViscosity primer

26-Oct-07 W.A. Zajc

Really, It’s A Meta-Talk

The dénouement!AdS/CFT connectionη/s values

26-Oct-07 W.A. Zajc

The Primacy of QCD� While the (conjectured) bound

is a purely quantum mechanical result . . .

�It was derived in and motivated by the Anti-de Sitter space / Conformal Field Theory c orrespondence

� Weak form:� “Four-dimensional N=4 supersymmetric SU(N c) gauge theory is equivalent

to IIB string theory with AdS 5 x S5 boundary conditions.”( The Large N limit of superconformal field theories a nd supergravity ,

J. Maldacena, Adv. Theor. Math. Phys. 2, 231, 1998 hep-th/9711200 )

� Strong form:� “Hidden within every non-Abelian gauge theory, even within the weak

and strong nuclear interactions, is a theory of qua ntum gravity.”( Gauge/gravity duality , G.T. Horowitz and J. Polchinski, gr-qc/0602037 )

� Strongest form: Only with QCD can we explore experimentally these fascinating connections over the full range of the coupling constant to study QGP

πη

4

h≥s

≡≡≡≡ Quantum Gauge Phluid

26-Oct-07 W.A. Zajc

The (Assumed) Connection� Exploit Maldacena’s

“D-dimensional strongly coupled gauge theory ⇔⇔⇔⇔ (D+1)-dimensional stringy gravity”

� Thermalize with massive black brane

� Calculate viscosity ηηηη = “Area”/16 ππππG

� Normalize by entropy (density) s = “Area” / 4G

� Dividing out the infinite “areas” :

� Conjectured to be a lower bound “ for all relativistic quantum field theories at finite temperature and zero chemical po tential ”.

� See “ Viscosity in strongly interacting quantum field the ories from black hole physics ”, P. Kovtun, D.T. Son, A.O. Starinets, Phys.Rev.Lett.94:111601, 2005, hep-th/0405231

Infinite “Area” !

πη

4

1)(

ks

h=

hµν

Aµ

Aν

26-Oct-07 W.A. Zajc

New Dimensions in RHIC Physics� “ The stress tensor of a quark moving through N=4 thermal

plasma”, J.J. Friess et al ., hep-th/0607022

Our 4Our 4 --d d worldworld

String String theorist’s theorist’s

5+55+5--d d worldworld

The stuff formerly The stuff formerly known as QGPknown as QGP

Heavy quark Heavy quark moving moving through through

the the mediummediumEnergy loss Energy loss

from string from string dragdrag

Jet modifications Jet modifications from wake fieldfrom wake field

26-Oct-07 W.A. Zajc

Measuring η/s� Damping (flow, fluctuations, heavy quark motion) ~ ηηηη/s

� FLOW: Has the QCD Critical Point Been Signaled by Observations at RHIC?,R. Lacey et al., Phys.Rev.Lett.98:092301,2007 (nucl-ex/0609025)

� The Centrality dependence of Elliptic flow, the Hydrodynamic Limit, and the Viscosity of Hot QCD, H.-J. Drescher et al., (arXiv:0704.3553)

� FLUCTUATIONS: Measuring Shear Viscosity Using Transverse Momentum Correlations in Relativistic Nuclear Collisions, S. Gavin and M. Abdel-Aziz, Phys.Rev.Lett.97:162302,2006 (nucl-th/0606061)

� DRAG, FLOW: Energy Loss and Flow of Heavy Quarks in Au+Au Collisions at √sNN = 200 GeV (PHENIX Collaboration), A. Adare et al., to appear in Phys. Rev. Lett. (nucl-ex/0611018)

ππππηηηη

4

1)2.12.01.1( ±±±±±±±±====

s

ππππηηηη

4

1)8.30.1( −−−−====�

ππππηηηη

4

1)0.23.1( −−−−====�

ππππηηηη

4

1)5.29.1( −−−−====

s

CHARM!

26-Oct-07 W.A. Zajc

Has the QCD Critical Point Been Signaled by Observa tions at RHIC?,R. Lacey et al ., Phys.Rev.Lett.98:092301,2007 ( nucl-ex/0609025 )� Signature: FLOW� Calculation:

� Payoff Plot:

ππππηηηη

λλλλ

λλλληηηη

4

1)2.12.01.1(

fm03.03.0

05.035.0

MeV3165

~

±±±±±±±±====⇒⇒⇒⇒

±±±±====±±±±====

±±±±====

s

c

T

cTs

f

s

sf

Fit v2 ~I1(w)/I0(w); w = mT/2T

On-shell transport model for gluons, Z. Xu and C. Greiner, hep-ph/0406278.

PHENIX v2/ε data (nucl-ex/0608033) compared to R.S. Bhalerao et al. (nucl-th/0508009)

26-Oct-07 W.A. Zajc

Measuring Shear Viscosity Using Transverse Momentum Correlations in Relativistic Nuclear Collisions, S. Gavin and M. Abdel-Aziz, Phys.Rev.Lett.97:162302,2006 (nucl-th/0606061)

� Signature: FLUCTUATIONS� Calculation:

� Payoff Plot: ππππηηηη

ττττττττ

ττττττττηηηησσσσσσσσ

ττττττττττττ

ττττηηηησσσσσσσσ

ηηηη

4

1)8.31(

fm20~,fm1~

114

14

0

,,

22

0

020

2

2

−−−−====⇒⇒⇒⇒

−−−−====−−−−

−−−−====−−−−

====

∇∇∇∇−−−−∂∂∂∂∂∂∂∂

s

sT

sT

gsTt

CfPf

CfPfpc

f

f

Diffusion eq. for fluctuations g

Compare to STAR data on centrality dependence of rapidity width σ of pT fluctuations

Difference in correlation widths for central and peripheral collisions

26-Oct-07 W.A. Zajc

The Centrality dependence of Elliptic flow, the Hyd rodynamic Limit, and the Viscosity of Hot QCD , H.-J. Drescher et al ., (arXiv:0704.3553 )� Signature: FLOW� Calculation:

� Payoff Plot:

ππππηηηη

σσσσηηηη

εεεεεεεε

σσσσττττσσσσττττ

ρσρσρσρσλλλλ

4

1)5.29.1(

4,/264.1,31/,7.0

/1

1

)(111

0

0

22

−−−−====⇒⇒⇒⇒

================

++++

====

====

========≡≡≡≡

s

nsTcK

KKvv

cdydN

Ac

dydN

AR

RK

S

perfect

SS

Knudsen number K

Fits to PHOBOS v2 data to determine σ for Glauber and CGC initial conditions

Decrease in flow due to finite size

26-Oct-07 W.A. Zajc

Moore and Teaney Phys.Rev.C71:064904,2005(perturbative, argue ~valid non-perturbatively)

Energy Loss and Flow of Heavy Quarks in Au+Au Colli sions at √sNN = 200 GeV (PHENIX Collaboration), A. Adare et al ., Phys. Rev. Lett. 98:172301,2007 ( nucl-ex/0611018 )

� Signature: FLOW, ENERGY LOSS� Calculation:

� Payoff Plot:

(((( ))))

ππππηηηη

εεεεηηηηππππ

4

1)0.23.1(

3for6~)/(/

2)64(~

−−−−====⇒⇒⇒⇒

====++++

−−−−

s

NPD

TD

fHQ

HQ

Rapp and van HeesPhys.Rev.C71:034907,2005, to fit both PHENIX v2(e) and RAA(e)

26-Oct-07 W.A. Zajc

(Some) Things I’d Like To Know

� Are there better ways to extract η/s ?

� Can these existing estimates be improved ?� (In particular, can systematic errors be understood?)

� All of these methods rely on εεεε+P = Ts . �How does this change in the presence of a conserved charge

?

� In ordinary fluids, η/s has a pronounced minimum near the critical point.

�Can AdS/CFT say anything about this for gauge fluids?

26-Oct-07 W.A. Zajc

(More) Things I’d Like To Know

� Are AdS/CFT predictions falsifiable ? � What if Song and Heinz η/s < 1/4π is correct?

� Suppression of elliptic flow in a minimally viscous quark-gluon plasma, H. Song and U. Heinz, arXiv:0709.0742v1 .

� What if Mach cone angles different from data ?

� What if 1/√γγγγ not seen in J/Ψ suppression ?

� What data can best constrain initial conditions?� (Will we ever be able to eliminate this source of ambiguity

between Glauber, CGC, … ?)

� Are there AdS/CFT setups to do elliptic flow dynamically?�Can they say anything about the observed scaling ?

26-Oct-07 W.A. Zajc

The “Flow” Is Perfect� The “fine structure” v 2(pT) for different mass particles

shows good agreement with ideal (“perfect fluid”) hydrodynamics

� Roughly: ∂ννννTµνµνµνµν =0 →→→→ Work-energy theorem →→→→ ∫∫∫∫ ∇∇∇∇P d(vol) = ∆∆∆∆EK ≅≅≅≅ mT – m0 ≡≡≡≡

∆∆∆∆KET

~~

22TT pmKE +≡

26-Oct-07 W.A. Zajc

The “Flow” Knows Quarks� The “fine structure” v 2(pT) for different mass particles

shows good agreement with ideal (“perfect fluid”) hydrodynamics

� Scaling flow parameters by quark content n q resolves meson-baryon separation of final state hadrons

baryonsbaryons

mesonsmesons

26-Oct-07 W.A. Zajc

(More) Things I’d Like To Know� What does flow scaling tell us about degrees of freedom?

� Hadronic Modes and Quark Properties in the Quark-Gluon Plasma,M. Mannarelli and R. Rapp, arXiv:hep-ph/0505080v2 :m ~ 150 MeV , Γ ~ 200 MeV .

�Is any form of quasiparticle consistent with KSS bound?

� All(?) AdS/CFT calculations find drag ~ √λλλλ = √g2NC .

� What is this telling us about the degrees of freedom ?

� Is there a unique prescription for fixing coupling ?� Is there well-controlled expansion away from ‘t Hooft limit?� Calibrate it with lattice ‘data’ ?�ASIDE: Those who most often pronounce “AdS/CFT is useless because

the coupling doesn’t run” are those most likely to do calculations with αs = 0.5 .

26-Oct-07 W.A. Zajc

(Big ) Things I’d Like To Know

� Can one start from confining, chiral Sakai-Sugimoto and push it through a phase transition ?

� Hod tells us τ > 1 / π T. � Universal Bound on Dynamical Relaxation Times and B lack-Hole

Quasinormal Ringing , S. Hod, arXiv:gr-qc/0611004v1

�Can AdS/CFT address this ?

� What does it mean to have a gravity dual ?�In particular, how do I find it ?

�What is the impact of the KSS conjecture on other fields ?

26-Oct-07 W.A. Zajc

What Follows is the Un-Meta-Talk…

26-Oct-07 W.A. Zajc

Working Title: The Fluid Nature of QGP

� From the Oxford English Dictionary:1) Primary definition: (adj.) fluid :

"Having the property of flowing; consisting of particles that move freely among themselves, so as to give way before the slightest pressure. (A general term including both gaseous and liquid substances.)”

2) Secondary definition: (adj.)"Flowing or moving readily; not solid or rigid; not fixed, firm, or stable.”

� SUMMARY: Followinga) a discovery period, during which time our understanding of “quark-gluon plasma” was fluid(2), and b) a paradigm shift,we are now developing a solid understanding of the extraordinary fluid(1) produced at RHIC.

26-Oct-07 W.A. Zajc

Expectations circa 2000

As encoded in the Nuclear Physics Wall Chart,

http://www.lbl.gov/abc/wallchart/

RHIC would create a quark-gluon plasma;

a “gas” of weakly interacting

quarks and gluons

26-Oct-07 W.A. Zajc

The Plan circa 2000� Use RHIC’s unprecedented capabilities

� Large √s �����Access to reliable pQCD probes�Clear separation of valence baryon number and glue�To provide definitive experimental evidence for/aga inst

Quark Gluon Plasma (QGP)

� Polarized p+p collisions

� Two small detectors, two large detectors� Complementary capabilities� Small detectors envisioned to have 3-5 year lifetim e� Large detectors ~ facilities

�Major capital investments�Longer lifetimes�Potential for upgrades in response to discoveries

See earlier talk by M. Grosse Perdekamp

26-Oct-07 W.A. Zajc

RHIC and Its Experiments

STARSTAR

26-Oct-07 W.A. Zajc

Since Then…� Accelerator complex

� Routine operation at 2-4 x design luminosity (Au+Au )� Extraordinary variety of operational modes

� Species: Au+Au, d+Au, Cu+Cu, p ↑↑↑↑+p↑↑↑↑� Energies: 22 GeV (Au+Au, Cu+Cu, p ↑↑↑↑), 56 GeV (Au+Au),

62 GeV (Au+Au,Cu+Cu, p ↑↑↑↑+p↑↑↑↑) , 130 GeV (Au+Au), 200 GeV (Au+Au, Cu+Cu, d+Au, p ↑↑↑↑+p↑↑↑↑), 410 GeV (p↑↑↑↑), 500 GeV (p↑↑↑↑)

� Experiments: � Worked !

� Science� >160 refereed publications, among them > 90 PRL’s� Major discoveries

� Future� Demonstrated ability to upgrade� Key science questions identified� Accelerator and experimental upgrade program

underway to perform that science

26-Oct-07 W.A. Zajc

ApproachWill present sample of results from various points of the collision process:

1. Final State

Yields of produced particles

Thermalization, Hadrochemistry

2. Initial State

Hydrodynamic flow from

initial spatial asymmetries

3. Probes of dense matter

26-Oct-07 W.A. Zajc

Assertion� In these complicated events, we have

(a posteriori ) control over the event geometry:

� Degree of overlap

� Orientation with respect to overlap

Reaction

Reaction

PlanePlane

““ Central”Central” ““ Peripheral”Peripheral”

26-Oct-07 W.A. Zajc

Language

� We all have in common basic nuclear properties

� A, Z …

� But specific to heavy ion physics

� v2

�RAA

� T� µµµµB

� ηηηη� s

1 if yield = perturbative value from initial parton -parton flux

Fourier coefficient of azimuthal anisotropies ���� “flow”

Temperature ( MeV)

Baryon chemical potential ( MeV) ~ net baryon density

Viscosity ( MeV 3 )

Entropy density ( MeV 3 ) ~ “particle” density

26-Oct-07 W.A. Zajc

Final StateDoes the huge abundance of final state particles reflect a thermal distribution?:

1. Final State

Yields of produced particles

Thermalization, Hadrochemistry

Consistent with thermal production

T ~ 170 MeV , µµµµB ~ 30 MeV

26-Oct-07 W.A. Zajc

RHIC’s Two Major Discoveries� Discovery of

strong “elliptic” flow:� Elliptic flow in Au + Au collisions at √sNN= 130 GeV, STAR Collaboration, ( K.H. Ackermann et al. ). Phys.Rev.Lett.86:402-407,2001

� 318 citations

� Discovery of “jet quenching”� Suppression of hadrons with large

transverse momentum in central Au+Au collisions at √sNN = 130 GeV, PHENIX Collaboration ( K. Adcox et al.), Phys.Rev.Lett.88:022301,2002

� 384 citations

26-Oct-07 W.A. Zajc

Initial StateHow are the initial state densities and asymmetries imprinted on the detected distributions?

3. Initial State

Hydrodynamic flow from

initial spatial asymmetries

26-Oct-07 W.A. Zajc

Motion Is Hydrodynamic

x

yz

� When does thermalization occur? � Strong evidence that final state bulk behavior

reflects the initial state geometry

� Because the initial azimuthal asymmetrypersists in the final statedn/d φφφφ ~ 1 + 2 v2(pT) cos (2 φφφφ) + ...

2v2

26-Oct-07 W.A. Zajc

The “Flow” Is Perfect� The “fine structure” v 2(pT) for different mass particles

shows good agreement with ideal (“perfect fluid”) hydrodynamics

� Roughly: ∂ννννTµνµνµνµν =0 →→→→ Work-energy theorem →→→→ ∫∫∫∫ ∇∇∇∇P d(vol) = ∆∆∆∆EK ≅≅≅≅ mT – m0 ≡≡≡≡

∆∆∆∆KET

~~

22TT pmKE +≡

26-Oct-07 W.A. Zajc

The “Flow” Knows Quarks� The “fine structure” v 2(pT) for different mass particles

shows good agreement with ideal (“perfect fluid”) hydrodynamics

� Scaling flow parameters by quark content n q resolves meson-baryon separation of final state hadrons

baryonsbaryons

mesonsmesons

26-Oct-07 W.A. Zajc

Probes of Dense MatterQ. How dense is the matter?A. Do pQCD Rutherford scattering on deep interior u sing“auto-generated” probes:

2. Probes of dense matter

26-Oct-07 W.A. Zajc

Baseline p+p Measurements with pQCD� Consider measurement of ππππ0’s in p+p

collisions at RHIC.� Compare to pQCD calculation

� Phys. Rev. Lett. 91, 241803 (2003)

),(

)(

),(),(

2

22

/

//

µ

σ

µµσ

hch

bBbaAa

zD

dcbad

xfxfd

⊗

+→+⊗

⊗=

∧

•parton distribution functions, for partons a and b•measured in DIS, universality

•perturbative cross-section (NLO)•requires hard scale

•factorization between pdf and cross section

•fragmentation function•measured in e+e-

26-Oct-07 W.A. Zajc

Au+Au: Systematic Suppression Pattern

� ≈ constancy for pT > 4 GeV/c for all centralities?

Suppressed

Suppressed

Enh

ance

dE

nhan

ced

26-Oct-07 W.A. Zajc

The Matter is Opaque� STAR azimuthal

correlation function shows ~ complete absence of “away-side” jet

�Partner in hard scatter is completely absorbedin the dense medium

GONE

∆Φ∆Φ∆Φ∆Φ=0

∆Φ∆Φ∆Φ∆Φ

∆Φ ∆Φ ∆Φ ∆Φ = ππππ

∆Φ ∆Φ ∆Φ ∆Φ = 0000

26-Oct-07 W.A. Zajc

Schematically (Partons)Scattered partons on the “near side” lose energy ,

but emerge;

those on the “far side” are totally absorbed

26-Oct-07 W.A. Zajc

Control: Photons shine, Pions don’t

� Direct photons are not inhibited by hot/dense medium� Rather: shine through consistent with pQCD

26-Oct-07 W.A. Zajc

Schematically (Photons)Scattered partons on the “near side” lose energy ,

but emerge;

the direct photon always emerges

26-Oct-07 W.A. Zajc

� This one figure encodes rigorous control of systematics

� in four different measurements over many orders of magnitude

Precision Probes

centralNcoll = 975 ± 94

== ==

26-Oct-07 W.A. Zajc

Connecting Soft and Hard RegimesScattered partons on the “near side” lose energy ,

but emerge;

those on the “far side” are totally absorbed →→ Really ?Really ?

26-Oct-07 W.A. Zajc

� Mach cone?☑ Jets travel faster than the

speed of sound in the medium.

☑ While depositing energy via gluon radiation.

�QCD “sonic boom” (?)

�To be expectedin a dense fluidwhich is strongly-coupled

Fluid Effects on Jets ?

26-Oct-07 W.A. Zajc

High pT Parton → Low pT “Mach Cone”?� The “ disappearance ”

is that of the high p T partner

� But at low p T, see re-appearance

� and

� “Side-lobes”(Mach cones?)

26-Oct-07 W.A. Zajc

Suggestion of Mach Cone?� Modifications to di-jet hadron pair correlations in Au+Au collisions at √sNN = 200 GeV,

PHENIX Collaboration (S.S. Adler et al.), Phys.Rev.Lett.97:052301,2006

A “perfect”fluid response!

∆Φ∆Φ∆Φ∆Φ

26-Oct-07 W.A. Zajc

How Perfect is “Perfect” ?� All “realistic” hydrodynamic calculations for RHIC f luids to

date have assumed zero viscosity� η η η η = 0 ���� “perfect fluid”� But there is a (conjectured) quantum limit:

“ A Viscosity Bound Conjecture ”, P. Kovtun , D.T. Son, A.O. Starinets , hep-th/0405231

� Where do “ordinary”fluids sit wrtthis limit?

� RHIC “fluid” mightbe at ~1 on this scale (!)

T=10T=101212 KK

(( 44π)π)

sDensityEntropyππππππππ

ηηηη4

)(4

hh ≡≡≡≡≥≥≥≥

26-Oct-07 W.A. Zajc

� Remove your organic prejudices� Don’t equate viscous with “sticky” !

� Think instead of a not-quite-ideal fluid:� “not-quite-ideal” ≡≡≡≡ “supports a shear stress”� Viscosity ηηηη

then defined as

� Dimensional estimate:

� small viscosity ���� Large cross sections

�Large cross sections ���� strong couplings

�Strong couplings ���� perturbation theory difficult !

Viscosity Primer

yv

AF xx

∂∂∂∂∂∂∂∂−−−−==== ηηηη

σσ

1

)()(η

pn

pnmfppn

pathfreemeandensitymomentum

========≈≈≈≈

××××≈≈≈≈

26-Oct-07 W.A. Zajc

The Primacy of QCD� While the (conjectured) bound

is a purely quantum mechanical result . . .

�It was derived in and motivated by the Anti-de Sitter space / Conformal Field Theory c orrespondence

� Weak form:� “Four-dimensional N=4 supersymmetric SU(N c) gauge theory is equivalent

to IIB string theory with AdS 5 x S5 boundary conditions.”( The Large N limit of superconformal field theories a nd supergravity ,

J. Maldacena, Adv. Theor. Math. Phys. 2, 231, 1998 hep-th/9711200 )

� Strong form:� “Hidden within every non-Abelian gauge theory, even within the weak

and strong nuclear interactions, is a theory of qua ntum gravity.”( Gauge/gravity duality , G.T. Horowitz and J. Polchinski, gr-qc/0602037 )

� Strongest form: Only with QCD can we explore experimentally these fascinating connections over the full range of the coupling constant to study QGP

πη

4

h≥s

≡≡≡≡ Quantum Gauge Phluid

26-Oct-07 W.A. Zajc

The (Assumed) Connection� Exploit Maldacena’s

“D-dimensional strongly coupled gauge theory ⇔⇔⇔⇔ (D+1)-dimensional stringy gravity”

� Thermalize with massive black brane

� Calculate viscosity ηηηη = “Area”/16 ππππG

� Normalize by entropy (density) s = “Area” / 4G

� Dividing out the infinite “areas” :

� Conjectured to be a lower bound “ for all relativistic quantum field theories at finite temperature and zero chemical po tential ”.

� See “ Viscosity in strongly interacting quantum field the ories from black hole physics ”, P. Kovtun, D.T. Son, A.O. Starinets, Phys.Rev.Lett.94:111601, 2005, hep-th/0405231

Infinite “Area” !

πη

4

1)(

ks

h=

hµν

Aµ

Aν

See next talk: QGP- Theoretical Overview , U. Wiedemann

26-Oct-07 W.A. Zajc

New Dimensions in RHIC Physics� “ The stress tensor of a quark moving through N=4 thermal

plasma”, J.J. Friess et al ., hep-th/0607022

Our 4Our 4 --d d worldworld

String String theorist’s theorist’s

5+55+5--d d worldworld

The stuff formerly The stuff formerly known as QGPknown as QGP

Heavy quark Heavy quark moving moving through through

the the mediummediumEnergy loss Energy loss

from string from string dragdrag

Jet modifications Jet modifications from wake fieldfrom wake field

26-Oct-07 W.A. Zajc

Measuring η/s� Damping (flow, fluctuations, heavy quark motion) ~ ηηηη/s

� FLOW: Has the QCD Critical Point Been Signaled by Observations at RHIC?,R. Lacey et al., Phys.Rev.Lett.98:092301,2007 (nucl-ex/0609025)

� The Centrality dependence of Elliptic flow, the Hydrodynamic Limit, and the Viscosity of Hot QCD, H.-J. Drescher et al., (arXiv:0704.3553)

� FLUCTUATIONS: Measuring Shear Viscosity Using Transverse Momentum Correlations in Relativistic Nuclear Collisions, S. Gavin and M. Abdel-Aziz, Phys.Rev.Lett.97:162302,2006 (nucl-th/0606061)

� DRAG, FLOW: Energy Loss and Flow of Heavy Quarks in Au+Au Collisions at √sNN = 200 GeV (PHENIX Collaboration), A. Adare et al., to appear in Phys. Rev. Lett. (nucl-ex/0611018)

ππππηηηη

4

1)2.12.01.1( ±±±±±±±±====

s

ππππηηηη

4

1)8.30.1( −−−−====�

ππππηηηη

4

1)0.23.1( −−−−====�

ππππηηηη

4

1)5.29.1( −−−−====

s

CHARM!

26-Oct-07 W.A. Zajc

Has the QCD Critical Point Been Signaled by Observa tions at RHIC?,R. Lacey et al ., Phys.Rev.Lett.98:092301,2007 ( nucl-ex/0609025 )� Signature: FLOW� Calculation:

� Payoff Plot:

ππππηηηη

λλλλ

λλλληηηη

4

1)2.12.01.1(

fm03.03.0

05.035.0

MeV3165

~

±±±±±±±±====⇒⇒⇒⇒

±±±±====±±±±====

±±±±====

s

c

T

cTs

f

s

sf

Fit v2 ~I1(w)/I0(w); w = mT/2T

On-shell transport model for gluons, Z. Xu and C. Greiner, hep-ph/0406278.

PHENIX v2/ε data (nucl-ex/0608033) compared to R.S. Bhalerao et al. (nucl-th/0508009)

26-Oct-07 W.A. Zajc

Measuring Shear Viscosity Using Transverse Momentum Correlations in Relativistic Nuclear Collisions, S. Gavin and M. Abdel-Aziz, Phys.Rev.Lett.97:162302,2006 (nucl-th/0606061)

� Signature: FLUCTUATIONS� Calculation:

� Payoff Plot: ππππηηηη

ττττττττ

ττττττττηηηησσσσσσσσ

ττττττττττττ

ττττηηηησσσσσσσσ

ηηηη

4

1)8.31(

fm20~,fm1~

114

14

0

,,

22

0

020

2

2

−−−−====⇒⇒⇒⇒

−−−−====−−−−

−−−−====−−−−

====

∇∇∇∇−−−−∂∂∂∂∂∂∂∂

s

sT

sT

gsTt

CfPf

CfPfpc

f

f

Diffusion eq. for fluctuations g

Compare to STAR data on centrality dependence of rapidity width σ of pT fluctuations

Difference in correlation widths for central and peripheral collisions

26-Oct-07 W.A. Zajc

The Centrality dependence of Elliptic flow, the Hyd rodynamic Limit, and the Viscosity of Hot QCD , H.-J. Drescher et al ., (arXiv:0704.3553 )� Signature: FLOW� Calculation:

� Payoff Plot:

ππππηηηη

σσσσηηηη

εεεεεεεε

σσσσττττσσσσττττ

ρσρσρσρσλλλλ

4

1)5.29.1(

4,/264.1,31/,7.0

/1

1

)(111

0

0

22

−−−−====⇒⇒⇒⇒

================

++++

====

====

========≡≡≡≡

s

nsTcK

KKvv

cdydN

Ac

dydN

AR

RK

S

perfect

SS

Knudsen number K

Fits to PHOBOS v2 data to determine σ for Glauber and CGC initial conditions

Decrease in flow due to finite size

26-Oct-07 W.A. Zajc

Moore and Teaney Phys.Rev.C71:064904,2005(perturbative, argue ~valid non-perturbatively)

Energy Loss and Flow of Heavy Quarks in Au+Au Colli sions at √sNN = 200 GeV (PHENIX Collaboration), A. Adare et al ., Phys. Rev. Lett. 98:172301,2007 ( nucl-ex/0611018 )

� Signature: FLOW, ENERGY LOSS� Calculation:

� Payoff Plot:

(((( ))))

ππππηηηη

εεεεηηηηππππ

4

1)0.23.1(

3for6~)/(/

2)64(~

−−−−====⇒⇒⇒⇒

====++++

−−−−

s

NPD

TD

fHQ

HQ

Rapp and van HeesPhys.Rev.C71:034907,2005, to fit both PHENIX v2(e) and RAA(e)

26-Oct-07 W.A. Zajc

RHIC and the Phase “Transition”� The lattice tells us that collisions at RHIC map ou t the

interesting region from

� High T init~ 300 MeV

to

� Low T final~ 100 MeV

30

)( 2

4

πε =T

T

Recall per masslessdegree of freedom

?

26-Oct-07 W.A. Zajc

LHC� How could we not choose to investigate “QGP” at ever y

opportunity?� LHC offers unparalleled

increase in √s� Will this too create a

strongly-coupled fluid?

� Active pursuit via � Dedicated experiment (ALICE)� Targeted studies (CMS, ATLAS)

26-Oct-07 W.A. Zajc

World Context

: 2009→→→→

: 2000→→→→RHIC II →→→→

: 2012→→→→

26-Oct-07 W.A. Zajc

RHIC

Physics for Many INPC’s To Come!

� Exploration� ~ Completed� Discovery!

� Characterization� Photon+Jet� Heavy Flavor� Energy Scans

� Exploitation(of upgrade potential)� Source � Detectors� Luminosity

RHIC →→→→ RHIC II

� Preparation�

�

�

� (Anticipation)� Exploration

� ~ Completed� Discovery!

� Characterization� Photon+Jet� Heavy Flavor� Energy Scans

Exploitation

LHC

� Preparation�

�

�

� (Anticipation)� Exploration

� ~ Completed� Discovery!

� Characterization� Photon+Jet� Heavy Flavor

Energy Scans

GSI-FAIR