john harris (yale) physics & astronomy colloquium, wayne state u. 12-4-08 recreating the...
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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
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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
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
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)
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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)
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Relativistic Heavy Ion Collider
RHIC BRAHMSPHOBOS
PHENIXSTAR
AGS
TANDEMS
3.8 km circle
v = 0.99995
speed of light
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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?
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
How do RHIC Collisions Evolve?
b
1) Superposition of independent p+p:
momenta randomrelative to reaction plane
Reaction plane
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
How do RHIC Collisions Evolve?
b
1) Superposition of independent p+p:
2) Evolution as a bulk system
momenta randomrelative to reaction plane
High densitypressureat center
“zero” pressurein surrounding vacuum
Pressure gradients (larger in-plane) push bulk “out” “flow”
more, faster particles seen in-plane
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
1) Superposition of independent p+p:
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
momenta randomrelative to reaction plane
Azimuthal Angular Distributions
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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
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
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
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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
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
hadrons
leading particle
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
Photons
Hadrons factor 4 – 5 suppression
dev/
AAAA /
coll pp
NR
N N
Deviations from binary scaling of hard collisions:
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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 ^
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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!
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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.
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
Hard Scattering (Jets) as a Probe of Dense Matter II
Can we see jets in high energy Au+Au?
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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
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 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) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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)
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
• 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
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 statesJohn 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
~ 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
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 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
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
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
John Harris (Yale) Physics & Astronomy Colloquium, Wayne State U. 12-4-08
- 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
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