Recreating the Primordial Quark-Gluon Soup
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
then at 10 m-seconds
& 2 x 1012 Kelvin
Quark-to-hadron
phase transition
On the “First Day”
Quark-Gluon Plasma
Rapid inflation
gravity
gravity, strong & E-W
forces separate
electromagnetism
There was light!
at 10-43 seconds
weak
strong
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Behavior of QCD at High Temperature
e/T4 ~ # degrees of freedom
e
 2
30
T4
many d.o.f.deconfined
F. Karsch, et al.
Nucl. Phys. B605
(2001) 579
TC ~ 175  8 MeV  eC ~ 0.3 - 1 GeV/fm3
few d.o.f.confined
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Modifications to QCD Coupling Constant s
heavy quark-antiquark coupling at finite T from lattice QCD
O.Kaczmarek, hep-lat/0503017
Nobel Prize 2004
D. Gross
H.D. Politzer
F. Wilczek
QCD Asymptotic Freedom (1973)
Constituents Hadrons,
dressed quarks,
quasi-hadrons,
resonances?
Coupling strength
varies
investigates
(de-)confinement,
hadronization,
& intermediate
objects.
“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.”
low Q2
high Q2
David Gross,
Nobel Lecture (RMP 05)
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Phase Diagram of QCD Matter
Early universe
LHC
Tc ~ 170 MeV
Temperature
see: Alford, Rajagopal, Reddy, Wilczek
Phys. Rev. D64 (2001) 074017
quark-gluon plasma
RHIC
Critical point ?
color
superconductor
hadron gas
nucleon gas
nuclei
Neutron stars
CFL
r0
vacuum
John Harris (Yale)
baryon density
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Quark-Gluon
Quark-Gluon
Plasma
Plasma
(Soup)
• 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 (?)
• Can we make it in the lab?
• Establish properties of QCD at high T (and density?)
JohnHarris
Harris
(Yale)
John
(Yale)
U.&Texas
– Austin,
Colloquium,
14 Nov.
2007
Physics
Astronomy
Colloquium,
Wayne State
U. 12-4-08
Relativistic Heavy Ion Collider
3.8 km circle
PHOBOS
PHENIX
RHIC
BRAHMS
STAR
AGS
TANDEMS
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Ultra-Relativistic Heavy Ion Collisions (at RHIC)
Interaction of Au nuclei complete
in t  few tenths fm/c
Gold nucleus
diameter = 14 fm
g = 100
(Lorenz contracted)
t = (14 fm/c) / g ~ 0.1 fm/c
General Orientation
Hadron (baryons, mesons) masses ~ 1 GeV
Hadron sizes ~ 10-15 meters (1 fm ≡ 1 fermi)
John Harris (Yale)
RHIC Collisions
Ecm = 200 GeV/nn-pair
Total Ecm = 40 TeV
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Ultra-Relativistic Heavy Ion Collision at RHIC
John Harris (Yale)
Hadron 07 - Frascati, Italy, 8 -13 Oct. 2007
On the “First Day” (at RHIC)
PHOBOS
Initial Observations:
Large produced particle multiplicities
ed. - “less than expected! gluon-saturation?”
 dnch/dh |h=0 = 670, Ntotal ~ 7500
Au + Au
CGC?
> 15,000 q +q in final state, > 92% are produced quarks
Large energy densities (dn/dh, dET/dh)
 e  5 GeV/fm3
PHENIX
e  5 - 15 ecritical
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
1
Quark flow & coalescence  constituent quark degrees of freedom!
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
How do RHIC Collisions Evolve?
1) Superposition of independent p+p:
momenta random
relative to reaction plane
Reaction plane
b
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
How do RHIC Collisions Evolve?
1) Superposition of independent p+p:
High density
pressure
at center
momenta random
relative to reaction plane
2) Evolution as a bulk system
Pressure gradients (larger in-plane)
push bulk “out”  “flow”
more, faster particles
seen in-plane
b
John Harris (Yale)
“zero” pressure
in surrounding vacuum
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Azimuthal Angular Distributions
1) Superposition of independent p+p: N
momenta random
relative to reaction plane
0
/4
/2
0
/4
/2
3/4

3/4

-RP (rad)
2) Evolution as a bulk system
Pressure gradients (larger in-plane)
push bulk “out”  “flow”
more, faster particles
seen in-plane
John Harris (Yale)
N
-RP (rad)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
1
On the First Day at RHIC - Azimuthal Distributions
STAR, PRL90 032301 (2003)
b ≈ 6.5 fm
b ≈ 4 fm
“central” collisions
midcentral
collisions
Top view
Beams-eye view
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
1
On the First Day at RHIC - Azimuthal Distributions
STAR, PRL90 032301 (2003)
b ≈ 10 fm
b ≈ 6.5 fm
b ≈ 4 fm
peripheral collisions
Top view
Beams-eye view
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
1
Elliptic Flow Saturates
Hydrodynamic Limit
z
• Azimuthal asymmetry of charged
particles:
dn/d ~ 1 + 2 v2(pT) cos (2 ) + ...
y
x
Mass dependence of v2
Requires • Early thermalization
(0.6 fm/c)
curves = hydrodynamic flow
zero viscosity, Tc = 165 MeV
• Ideal hydrodynamics
(zero viscosity)
 “nearly perfect fluid”
• e ~ 25 GeV/fm3 ( >> ecritical )
• Quark-Gluon Equ. of State
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Identified Hadron Elliptic Flow Complicated
Complicated v2(pT) flow pattern is observed for identified hadrons
d2n/dpTd ~ 1 + 2 v2(pT) cos (2 )
15000 quarks
flow collectively
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)
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
If baryons and mesons form
from independently flowing quarks
then
quarks are deconfined
for a brief moment (~ 10 -23 s), then hadronization!
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Universality of Classical Strongly-Coupled Systems?
Transport in gases of strongly-coupled atoms
RHIC fluid behaves like this –
a strongly coupled fluid.
Universality of classical strongly-coupled systems?
 Atoms, sQGP, ……. AdS/CFT……
K.M. O’Hara et al
Science 298 (2002) 2179
AdS5/CFT – a 5D Correspondence of 4D Systems
our world - 3 + 1 dim brane
horizon
Extra dimension
(the bulk)
• Analogy between black hole physics
and equilibrium thermodynamics
• Solutions possess hydrodynamic characteristics
Similar to fluids – viscosity, diffusion constants,….
MULTIPLICITY
Entropy  Black Hole Surface Area
DISSIPATION
Use strongly coupled
N = 4 SUSY YM theory.
Viscosity  Graviton Absorption
Derive a quantum lower viscosity bound: h/s > 1/4
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Ultra-low (Shear)Viscosity Fluids
4  h/s
h/s (water) >10
h/s (limit) = 1/4
QGP
T = 2 x 1012 K
Quantum lower viscosity bound: h/s > 1/4
(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!
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
“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/
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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)
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Particles are thermally distributed and flow collectively,
at universal hadronization temperature T = 177 MeV!
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
On the “Second” Day (~ Year) at RHIC
Probing Hot QCD Matter with Hard-Scattered Probes
leading particle
hadrons
hadrons
leading particle
 parton energy loss: modification of jets and leading particles & jet-correlations
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
High Momentum Hadrons Suppressed - Photons Not
Deviations fromdevbinary scaling of hard collisions: RAA
 /g
N AA

N coll N pp/ g
Photons
Hadrons
factor 4 – 5
suppression
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Dynamical Origin of High pT Hadron Suppression?
How does parton
lose energy?
What happens to the radiation?
eE
q ~ m
L
What is the dependence
on the type of parton?
For collisional energy loss
what about recoil energy?
DEgluon > DEquark, m=0 > DEquark, m>0
Important to measure DE of gluons  light  heavy quarks…
One parameterization of energy loss 
John Harris (Yale)
^ = m2 / L
q
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
^ Parameterization of Parton Energy Loss
q
Eskola, Honkanen, Salgado, Wiedemann
Nucl Phys A747 (2005) 511
q ~ m
L
q^ = 5 – 15 GeV2 / fm
John Harris (Yale)
from RHIC RAA Data
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Interpretation of the Parton Energy Loss
Energy loss requires large
2
qˆ  5 -- 10
15 GeV /fm
(also : Dainese, Loizides, Paic, hep-ph/0406201)
RHIC data
sQGP
q ~ m
L
QGP
Pion gas
Cold nuclear matter
R. Baier, Nucl Phys A715, 209c
John Harris (Yale)
F. Karsch, et al.
Nucl. Phys. B605
(2001) 579
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Heavy Quark Suppression
Using fixed order next-to-leading
log (FONL) cross sections
Armesto, Cacciari, Dainese, Salgado, Wiedemann,
PLB637:362, 2006
for charm and
beauty
Insufficient
Suppression
from theoretical
models!
Important to measure DE of gluons  light  heavy quarks…
DEgluon > DEquark, m=0 > DEquark, m>0
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
AdS5/CFT Again! - Initial Results:Parton Energy Loss
from J. J. Friess, S. S. Gubser and
G. Michalogiorgakis,arXiv:hep-th/0605292.
3+1D
H. Liu, K. Rajagopal and U. A. Wiedemann,
arXiv:hep-ph/0605178, recent PRL
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Hard Scattering (Jets) as a Probe of Dense Matter II
STAR p + p  jet event
JetSTAR
eventAu+Au
in e+e-(jet?)
collision
event
Can we see jets in high energy Au+Au?
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Hard Scattering (Jets) as a Probe of Dense Matter II
200 GeV Au + Au central collision (STAR)
Ejet = 21 GeV
Can we see jets in high energy Au+Au?
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Where Does the Energy Go?
dev
correlations
JetJet
correlations
in in
central
Gold-Gold.
central
Gold-Gold.
proton-proton
reactions.
Away
side
Away
side
jet jet
Color wakes?
disappears
for
reappears
inMüller
particles
Strong
J. Ruppert
& B.back-topT > 2 GeV
pT >particles
200peaks.
MeV
back
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
Azimuthal Angular Correlations
Lost energy of away-side jet is redistributed to rather large angles!
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
The suppression of high pT hadrons and the quenching of jets
indicates the presence of a high density, strongly-coupled
colored medium. !
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
“Basic” Summary from RHIC
Have created the hottest matter ever on Earth
T > 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
x
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!
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Geneva with Large Hadron Collider Superimposed
RHIC and LHC:
Cover 2 – 3 decades of energy (sNN ~ 20 GeV – 5.5 TeV)
What
the(Yale)
properties of hot QCD in this
temperature
range (T
~ 150
– 600
John are
Harris
Hadron
07 - Frascati,
Italy,
8 -13
Oct.MeV)?
2007
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
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Simple Expectations – Heavy Ion Interactions at LHC
√sNN (GeV)
SPS
17
RHIC
200
LHC
5500
T / Tc
e (GeV/fm3)
1.1
3
1.9
5
3.0 - 4.2
15-60
hotter
denser
tQGP (fm/c)
≤2
2-4
> 10
longerlived
factor 28
Lead nucleus
diameter ~ 14 fm
g = 2,700
(Lorenz contracted)
t ~ (14 fm/c) / g < 0.01 fm/c
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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 states
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
The ALICE Heavy Ion Experiment
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
ALICE Collaboration
Spain/Cuba
Romania
Japan Brazil
South Africa
Korea
USA
China
India Croatia
Armenia
Ukraine
Mexico
JINR
Italy
Russia
France
Netherlands
Hungary
UK
Greece
Sweden
Germany
Finland
Poland
Norway
Slovak Rep.
Czech Rep.
~ 1000 Members
~ 30 Countries
CERN
Denmark
~ 100 Institutes
• 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
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
The ALICE Experiment Installation
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Heavy Ion Physics at the LHC
LHC 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?
LHC
Particle Multiplicities
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Heavy Ion Physics at the LHC
LHC 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
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Hard Probes with LHC Heavy Ions
Significant increase in hard cross sections
(pT or mass > 2 GeV/c) at LHC –
 slarge pT /stotal ~
s
Rate
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)
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Jet-finding - Learning from Tevatron & RHIC
p + p experience (CDF)
- most of energy within cone of
Au + Au experience (STAR) - HI Background
Must
 suppress “soft” background:
h
- small jet cones R = 0.3-0.4
pT /cell (GeV/c)
R =  (Dh2 + D2) < 0.3
200 GeV Au + Au central collision (STAR)
Ejet = 21 GeV
- pT cut: pT > 1 – 2 GeV/c
- EbyE out-of-cone background energy
h
John Harris (Yale)

Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Hard Probes in ALICE
Heavy Quarks
(mass/color dependence of parton energy-loss)
Displaced vertices (Do  K- +) from tracking
• Electrons from Transition Radiation Detector & EMCal
•
Quarkonia
(initial temperature, Debye color screening, recombination)
•
J/y, , ’ (excellent),
’’(2-3 yrs),
y’ (very difficult)
V(r)
Confined
Bound state (e.g. J/y)
c
c
Deconfined
r
Color Screening
Color screening of cc pair
results in J/y (cc) suppression!
John Harris (Yale)
Quarkonium dissociation when
rDebye ~ 1/(sT) < rqq
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Hard Probes in ALICE
Heavy Quarks
(mass/color dependence of parton energy-loss)
Displaced vertices (Do  K- +) from tracking
• Electrons from Transition Radiation Detector & EMCal
•
Quarkonia
(initial temperature, Debye color screening, recombination)
•
J/y, , ’ (excellent),
’’(2-3 yrs),
y’ (very difficult)
T/TC
Karsch hep-lat/0502014v2
1/r [fm-1]
(1S)
J/y(1S)
b’(2P)
c(1P)
’’(3S)
’(2S)
John Harrismelting
(Yale U.)order of cc: ’, c, J/y
Measure
US ’’,
LHC’,
User’s
bb:
 Meeting, 24 October 2008
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 +
US Members:
Cal. St. U. – San Luis Obispo
Creighton University
University of Houston
Hard Probes – Jet Quenching
Lawrence Berkeley Nat. Lab
•
Jets, g , pi-zeros, leading particles to large pT
Lawrence Livermore Nat. Lab
Oak Ridge National Lab
Ohio State University
Hard Probes – Heavy Quarks
Purdue University
•
Displaced vertices (Do  K- +) from TPC/ITS
University of Tennessee
•
Electrons in Transition Radiation Detector (TRD) Wayne State University
Yale University
Hard Probes – Quarkonia
Affiliated members:
Kent State University
•
J/y, , ’ (excellent), ’’(2-3 yrs),
y’ ???
University of Texas – Austin
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Questions – Quark-Gluon Plasma at RHIC & LHC
- 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……?
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Special Thanks for Contributions to This Presentation!!
Miklos Gyulassy
Mike Lisa
Thomas Ullrich
Urs Wiedemann
John Harris (Yale)
Physics & Astronomy Colloquium, Wayne State U. 12-4-08
The End