John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08 Recreating the Primordial Quark-Gluon Soup

John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08

Recreating the Primordial Quark-Gluon Soup

On the “First Day”

There was light!gravity electro-

magnetism

weakstrong

at 10-43 seconds

then at 10 m-seconds

& 2 x 1012 Kelvin

Quark-to-hadron

phase transition

Rapid inflation

gravity, strong & E-W

forces separate

Quark-Gluon Plasma


Behavior of QCD at High Temperature

few d.o.f.confined

many d.o.f.deconfined

F. Karsch, et al.Nucl. Phys. B605 (2001) 579

TC ~ 175 8 MeV eC ~ 0.3 - 1 GeV/fm3

e/T4 ~ # degrees of freedom

24

30T


Modifications to QCD Coupling Constant s

heavy quark-antiquark coupling at finite T from lattice QCD O.Kaczmarek, hep-lat/0503017

Constituents - Hadrons, dressed quarks, quasi-hadrons, resonances?

Coupling strength variesinvestigates (de-)confinement, hadronization, & intermediate objects.

low Q2high Q2

D. Gross

H.D. Politzer

F. Wilczek

QCD Asymptotic Freedom (1973)

Nobel Prize 2004

“Before [QCD] we could not go back further than 200,000 years after the Big Bang. Today…since QCD simplifies at high energy, we can extrapolate to very early times when nucleons melted…to form a quark-gluon plasma.” David Gross, Nobel Lecture (RMP 05)


Phase Diagram of QCD MatterTe

mp

erat

ure

baryon density

Early universe

nucleinucleon gas

hadron gascolor

superconductor

quark-gluon plasma

Tc

~ 1

70

Me

V

r0

Critical point ?

vacuum

CFLNeutron stars

see: Alford, Rajagopal, Reddy, Wilczek Phys. Rev. D64 (2001) 074017L

HC

RHIC


John Harris (Yale) U. Texas – Austin, Colloquium, 14 Nov. 2007

Quark-Gluon Plasma• Standard Model Lattice Gauge Calculations predict

QCD Deconfinement phase transition at T = 175 MeV

• Cosmology Quark-hadron phase transition in early Universe

• Astrophysics Cores of dense stars (?)

• Establish properties of QCD at high T (and density?)

• Can we make it in the lab?

Quark-Gluon Plasma (Soup)


Relativistic Heavy Ion Collider

RHIC BRAHMSPHOBOS

PHENIXSTAR

AGS

TANDEMS

3.8 km circle

v = 0.99995

speed of light


Ultra-Relativistic Heavy Ion Collisions (at RHIC)

General Orientation

Hadron (baryons, mesons) masses ~ 1 GeV

Hadron sizes ~ 10-15 meters (1 fm ≡ 1 fermi)

RHIC Collisions

Ecm = 200 GeV/nn-pair

Total Ecm = 40 TeV

Gold nucleusdiameter = 14 fm

g = 100 (Lorenz contracted)

t = (14 fm/c) / g ~ 0.1 fm/c

Interaction of Au nuclei complete in t few tenths fm/c


John Harris (Yale) Hadron 07 - Frascati, Italy, 8 -13 Oct. 2007

Ultra-Relativistic Heavy Ion Collision at RHIC

PHOBOS

Au + Au

On the “First Day” (at RHIC)

Large energy densities (dn/d , h dET/d )h

5 e GeV/fm3 5 - 15 e e critical

30 - 100 x nuclear density

Large collective flow

ed. - “completely unexpected!”

Due to large early pressure gradients, energy & gluon densities

Requires hydrodynamics and quark-gluon equation of state

Quark flow & coalescence constituent quark degrees of freedom!1

PHENIX

Initial Observations:Large produced particle multiplicities ed. - “less than expected! gluon-saturation?”

dnch/dh |h=0 = 670, Ntotal ~ 7500

> 15,000 q +q in final state, > 92% are produced quarksCGC?


How do RHIC Collisions Evolve?

b

1) Superposition of independent p+p:

momenta randomrelative to reaction plane

Reaction plane


How do RHIC Collisions Evolve?

b


2) Evolution as a bulk system


High densitypressureat center

“zero” pressurein surrounding vacuum

Pressure gradients (larger in-plane) push bulk “out” “flow”

more, faster particles seen in-plane



2) Evolution as a bulk system

Pressure gradients (larger in-plane) push bulk “out” “flow”

more, faster particles seen in-plane

N

-RP (rad)0 /2 /4 3/4

N

-RP (rad)0 /2 /4 3/4


Azimuthal Angular Distributions


On the First Day at RHIC - Azimuthal DistributionsSTAR, PRL90 032301 (2003)

b ≈ 4 fm

“central” collisions

b ≈ 6.5 fm

midcentral collisions

Top view

Beams-eye view

1


STAR, PRL90 032301 (2003)

b ≈ 4 fmb ≈ 6.5 fmb ≈ 10 fm

peripheral collisions

Top view

Beams-eye view

On the First Day at RHIC - Azimuthal Distributions1


Elliptic Flow Saturates Hydrodynamic Limit

• Azimuthal asymmetry of charged particles: dn/df ~ 1 + 2 v2(pT) cos (2 f) + ...

x

z

y

curves = hydrodynamic flowzero viscosity, Tc = 165 MeV

1

Mass dependence of v2

Requires -

• Early thermalization (0.6 fm/c)

• Ideal hydrodynamics (zero viscosity) “nearly perfect fluid”

• e ~ 25 GeV/fm3 ( >> ecritical

)

• Quark-Gluon Equ. of StateJohn Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08

Identified Hadron Elliptic Flow ComplicatedComplicated v2(pT) flow pattern is observed for identified hadrons

d2n/dpTdf ~ 1 + 2 v2(pT) cos (2 f)

Baryons

Mesons

If the flow established at quark level, it is predicted to be simple KET KET / nq , v2 v2 / nq , nq = (2, 3 quarks) for (meson, baryon)

15000 quarksflow collectively


If baryons and mesons form

from independently flowing quarks

then

quarks are deconfined

for a brief moment (~ 10 -23 s), then hadronization!


Transport in gases of strongly-coupled atoms

RHIC fluid behaves like this – a strongly coupled

fluid.

Universality of Classical Strongly-Coupled Systems?

Universality of classical strongly-coupled systems? Atoms, sQGP, ……. AdS/CFT…… K.M. O’Hara et al

Science 298 (2002) 2179

Use strongly coupled N = 4 SUSY YM theory.

Derive a quantum lower viscosity bound: /h s > 1/4p

AdS5/CFT – a 5D Correspondence of 4D Systems

• Analogy between black hole physics and equilibrium thermodynamics

• Solutions possess hydrodynamic characteristicsSimilar to fluids – viscosity, diffusion constants,….

our world - 3 + 1 dim brane

horizon

Extra dim

ension

(the bulk)

MULTIPLICITY

Entropy Black Hole Surface Area

DISSIPATION

Viscosity Graviton Absorption


Ultra-low (Shear)Viscosity Fluids

4p /h s

Quantum lower viscosity bound: /h s > 1/4p (Kovtun, Son, Starinets)

From strongly coupled N = 4 SUSY YM theory.

2-d Rel Hydro describes STAR v2 data with h/s 0.1 near lower bound!

/h s (limit) = 1/4p

/h s (water) >10

QGP

T = 2 x 1012 K


“The RHIC fluid may be the

least viscous fluid ever seen”

The American Institute of Physics

announced the RHIC quark-gluon liquid

as the top physics story of 2005!see http://www.aip.org/pnu/2005/


It Flows - Is It Really Thermalized?

“Chemical” equilibration (particle yields & ratios): Particles yields represent equilibrium abundances

universal hadronization temperature

Small net baryon density (K+/K-,B/B ratios) mB ~ 25 - 40 MeV

Chemical Freezeout Conditions T = 177 MeV, mB = 29 MeV T ~ Tcritical (QCD)


Particles are thermally distributed and flow collectively,

at universal hadronization temperature T = 177 MeV!


On the “Second” Day (~ Year) at RHIC

Probing Hot QCD Matter with Hard-Scattered Probes

hadrons

leading particle

hadrons

leading particle

parton energy loss: modification of jets and leading particles & jet-correlations


High Momentum Hadrons Suppressed - Photons Not

Photons

Hadrons factor 4 – 5 suppression

dev/

AAAA /

coll pp

NR

N N

Deviations from binary scaling of hard collisions:


Dynamical Origin of High pT Hadron Suppression?

What happens to the radiation?

For collisional energy losswhat about recoil energy?

DEgluon > DEquark, m=0 > DEquark, m>0

Important to measure DE of gluons light heavy quarks…

What is the dependenceon the type of parton?

e E

How does parton lose energy?

q = m2 / L ^One parameterization of energy loss

q ~ m

L


Parameterization of Parton Energy Loss

q ~ m

L

Eskola, Honkanen, Salgado, WiedemannNucl Phys A747 (2005) 511

q ^

q = 5 – 15 GeV2 / fm from RHIC RAA Data ^


Interpretation of the Parton Energy Loss

q ~ m

L

RHIC data

R. Baier, Nucl Phys A715, 209c

QGP

Pion gas

Cold nuclear matter

sQGP

Energy loss requires large(also : Dainese, Loizides, Paic, hep-ph/0406201)

2ˆ 5 10 GeV /fmq 5 - 15


F. Karsch, et al.Nucl. Phys. B605 (2001) 579

Heavy Quark SuppressionUsing fixed order next-to-leading

log (FONL) cross sections

for charm and

beauty

Armesto, Cacciari, Dainese, Salgado, Wiedemann,PLB637:362, 2006

Insufficient

Suppression

from theoretical

models!


Important to measure DE of gluons light heavy quarks… DEgluon > DEquark, m=0 > DEquark, m>0

AdS5/CFT Again! - Initial Results:Parton Energy Loss

H. Liu, K. Rajagopal and U. A. Wiedemann, arXiv:hep-ph/0605178, recent PRL

from J. J. Friess, S. S. Gubser and

G. Michalogiorgakis,arXiv:hep-th/0605292.


3+1D

Hard Scattering (Jets) as a Probe of Dense Matter II

Jet event in e+e- collision STAR p + p jet event

Can we see jets in high energy Au+Au?

STAR Au+Au (jet?) event


Hard Scattering (Jets) as a Probe of Dense Matter II

Can we see jets in high energy Au+Au?


200 GeV Au + Au central collision (STAR)

Ejet = 21 GeV

Where Does the Energy Go? dev

Jet correlations in proton-proton reactions.

Strong back-to-back peaks.

Jet correlations in central Gold-Gold.

Away side jet disappears for particles pT > 2 GeV

Jet correlations in central Gold-Gold.

Away side jet reappears in particles pT > 200 MeV

Azimuthal Angular CorrelationsLost energy of away-side jet is redistributed to rather large angles!

Color wakes?

J. Ruppert & B. Müller

Mach cone from sonic boom?

H. Stoecker

J. Casalderrey-Solana & E. Shuryak

Cherenkov-like gluon radiation?

I. Dremin

A. Majumder, X.-N. Wang

Medium-induced gluon radiation?

Polosa, C. Salgado


The suppression of high pT hadrons and the quenching of jets

indicates the presence of a high density, strongly-coupled

colored medium. !


“Basic” Summary from RHIC

Have created the hottest matter ever on EarthT > 2 x 1012 K > 100,000 times hotter than the core of Sun

It has characteristics of a soup of quarks and gluons

It flows like a liquid, better than any we know or have made

It is opaque to the most energetic parton probes

It has some properties predicted in AdS/CFT (string theory)with black hole in 5D projected onto our 4D world!

On the Horizon……..Heavy Ions in the Large Hadron Collider!

x


John Harris (Yale) Hadron 07 - Frascati, Italy, 8 -13 Oct. 2007

Geneva with Large Hadron Collider Superimposed

RHIC and LHC:

Cover 2 – 3 decades of energy (sNN ~ 20 GeV – 5.5 TeV)

What are the properties of hot QCD in this temperature range (T ~ 150 – 600 MeV)?

LHC Heavy Ion Program

LHC Heavy Ion Data-taking Pb + Pb at sNN = 5.5 TeV

(1 month per year)


• LHC Collider Detectors- ATLAS- CMS- ALICE

t ~ (14 fm/c) / g < 0.01 fm/c

g = 2,700 (Lorenz contracted)

Lead nucleusdiameter ~ 14 fm

Simple Expectations – Heavy Ion Interactions at LHC

tQGP (fm/c)

e (GeV/fm3)

T / Tc

√sNN (GeV) factor 28

2-4

5

1.9

200

RHIC

≤ 2

3

1.1

17

LHCSPS

5500

3.0 - 4.2 hotter

15-60 denser

> 10 longer-lived


Why Heavy Ions at the LHC?• Expect different timescales, shorter interaction times, higher energy (T) !

Does system still equilibrate rapidly?

Thermal model still applies? T still ~ Tc (lattice QCD)?

Does it flow?

Elliptic Flow change? v2 still saturated? More or less v2?

Is the QGP still strongly- (or weakly-) coupled?

Liquid? More like a gas? No longer “nearly-perfect” fluid flow?

Impact on energy loss!!

• Understand parton energy loss! – What are the microscopic processes?

mass and flavor dependence?

use high pT jets & tag heavy quark jets

• Understand response of the medium!

Strongly interacting quarks and gluons away-side response?

use punch-through & associated jet

• Color screening of the medium!

Deconfinement? (compare LQCD), initial T, other effects J/y & Y statesJohn Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08

The ALICE Heavy Ion Experiment


ALICE Collaboration

~ 1000 Members ~ 30 Countries ~ 100 Institutes

Sweden

PolandNorway

Russia

JINR

Japan BrazilRomania

Spain/Cuba

South AfricaUSA

ChinaCroatia

ArmeniaIndia

Korea

Ukraine

Mexico

Czech Rep.Slovak Rep.

CERNDenmark

Finland

Germany

France

Italy

GreeceUK

Hungary

Netherlands

• US Members

Cal. St. U. – San Luis Obispo Creighton University

University of Houston Lawrence Berkeley Nat. Lab

Lawrence Livermore Nat. Lab Oak Ridge National Lab

Ohio State University Purdue University

University of Tennessee Wayne State University

Yale University


The ALICE Experiment Installation


Heavy Ion Physics at the LHCLHC Heavy Ions –

• expectations based on pQCD predictions & RHIC results• a lesson from RHIC – guided by theory + versatility + “expect the unexpected”

Soft Physics (pT ≤ 2 GeV/c) with heavy ions at LHC – • smooth extrapolation from SPS RHIC LHC?

Particle Multiplicities

LHC


Heavy Ion Physics at the LHCLHC Heavy Ions –

• expectations based on pQCD predictions & RHIC results• a lesson from RHIC – guided by theory + versatility + “expect the unexpected”

Soft Physics (pT ≤ 2 GeV/c) with heavy ions at LHC – • smooth extrapolation from SPS RHIC LHC?• expansion dynamics different (initial state, flow, HBT, evolution of T,

strange/charm/beauty)

Elliptic Flow



Significant increase in hard cross sections

(pT or mass > 2 GeV/c) at LHC – slarge pT /stotal ~ 2% at SPS

50% at RHIC

98% at LHC• “real” jets, large pT processes• abundance of heavy flavors• probe early times, calculable

sbb (LHC ) ~ 100 sbb (RHIC)

scc (LHC) ~ 10 scc (RHIC)

s Rat

e

Hard Probes with LHC Heavy Ions

Jet-finding - Learning from Tevatron & RHIC

fh

p + p experience (CDF)

- most of energy within cone of

R = (Dh2 + Df2) < 0.3

p T /

cell

(GeV

/c)

hf

Au + Au experience (STAR) - HI Background

Must suppress “soft” background:

- small jet cones R = 0.3-0.4

- pT cut: pT > 1 – 2 GeV/c

- EbyE out-of-cone background energy

200 GeV Au + Au central collision (STAR)

Ejet = 21 GeV


Hard Probes in ALICEHeavy Quarks (mass/color dependence of parton energy-loss)

• Displaced vertices (Do K- p+) from tracking• Electrons from Transition Radiation Detector & EMCal

Quarkonia (initial temperature, Debye color screening, recombination)

• J/y, , ’ (excellent), ’’(2-3 yrs), y’ (very difficult)

Color Screening

cc

Color screening of cc pairresults in J/y (cc) suppression!

Confined

Deconfined

r

V(r)

Bound state (e.g. J/y)

Quarkonium dissociation when rDebye ~ 1/(asT) < rqq


Hard Probes in ALICEHeavy Quarks (mass/color dependence of parton energy-loss)

• Displaced vertices (Do K- p+) from tracking• Electrons from Transition Radiation Detector & EMCal

Quarkonia (initial temperature, Debye color screening, recombination)

• J/y, , ’ (excellent), ’’(2-3 yrs), y’ (very difficult)

John Harris (Yale U.) US LHC User’s Meeting, 24 October 2008

T/TC 1/r [fm-1]

(1S)

J/(1S)

c(1P)

’(2S)

b’(2P)

’’(3S)

Karsch hep-lat/0502014v2

Measure melting order of cc: Y’, cc, J/ y bb: U’’, U’, U

Summary – ALICE the Heavy Ion Experiment

ALICE is a versatile, heavy ion detector at the LHC

Overview:

Soft Probes – “ala RHIC” • Expansion dynamics different from RHIC• Soft physics measurements ala RHIC

+ extended PID• Day 1 physics +

Hard Probes – Jet Quenching• Jets, , g pi-zeros, leading particles to large pT

Hard Probes – Heavy Quarks• Displaced vertices (Do K- p+) from TPC/ITS• Electrons in Transition Radiation Detector (TRD)

Hard Probes – Quarkonia• J/y, , ’ (excellent), ’’(2-3 yrs), y’ ???

US Members: Cal. St. U. – San Luis Obispo Creighton University University of Houston Lawrence Berkeley Nat. Lab Lawrence Livermore Nat. Lab Oak Ridge National Lab Ohio State University Purdue University University of Tennessee Wayne State University Yale UniversityAffiliated members: Kent State University University of Texas – Austin


- How does the system evolve and thermalize from its initial state?

- What are the properties & constituents (vs. T) of the QGP?

- Can we understand parton energy loss at a fundamental level?

- How does hadronization take place?

- Is the QCD Phase Diagram featureless above Tc? Coupling strength vs T….

- Are there new phenomena?

- What’s the range of validity of the theories (non-pQCD, pQCD, strings)?

- Can there be new developments in theory (lattice, hydro, parton E-loss, string

theory…) and understanding……across fields……?

Questions – Quark-Gluon Plasma at RHIC & LHC


Special Thanks for Contributions to This Presentation!!

Miklos Gyulassy

Mike Lisa

Thomas Ullrich

Urs Wiedemann


The End

Documents

John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08 Recreating the Primordial Quark-Gluon Soup