Iowa State Colloquium 2/11/02

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Jet Tomography of the Gluon Plasma at RHIC
nucl-th/0106072

• QCD Motivation for AA

• Global Observables dN/dyd2pT, dET/dyd2pT

• Jet Quenching

• Jet Tomography

Miklos Gyulassy (Columbia Univ)
2/11/02 Iowa State
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RHIC Complex

• 3.83 km circ. collider
• 6 intersection regions
• 4 Experiments
• pp, pA, AB
• Energy
• 500 GeV for p-p
• 200 GeV for Au-Au(per N-N collision)
• Luminosity
• Au-Au 2 x 1026 cm-2 s-1
• p-p 2 x 1032 cm-2 s-1 (polarized)

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3
5
1
4
1
2
3
Si28
Ecm100 AGeV
Ag107
1050
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Rapidity and Proper Time Coordinates
Boost Invariancegt DV t Dy pR2 1D
Hubble Expansion
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Lattice QCD vs Ideal (Stefan-Boltzmann) Pressure
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QCD Equation of State
Lattice QCD, MILC 97
Bag Model
E/VT4
3P/T4
T (GeV 1013 K)
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Mini-Bang at RHIC AuAu 130AGeV
How can we relate AA Experimental data to dense
QCD Dynamics and Thermodynamics??
Nhadrons4000
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Ions Approach t-15 fm/c
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Creation of Matter t5 fm/c
?Quark Gluon Plasma ?
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Color White Hadronization t10
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Global Constraints onInitial Conditions at RHIC
Gluon Showers
Soft vs Hard QCD Dynamics
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Au197 Au197--gt 5000
Ecm200 AGeV
BRAHMS/RHIC 2001
700
5
10
20
dN/dy 1.15 dN/dh
b
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Global Evidence for Gluon Showers at RHIC?
X.N. Wang, MG, PRL86(01)3496
EKRT
STAR PHENIX BRAHMS
soft physics
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Two Component Models
A4/3
A1
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SoftHard Dynamics in pp
HIJING P02GeV
XN Wang, MG
HIJING TAB(b)X pQCD ptgtp0Pythia
Npart(b)XBeam Jet StringsLUND,DPM
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XN Wang, MG
P02GeV
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Initial Conditions from
XNWang, MG, PRL86(01)3496
Centrality Dependence of dNch/dh
Npart
dNg(pTgt2)/dy200 HIJING rglue (t00.1 fm/c)
10/fm3 dNg(pTgt1)/dy1000 EKRT rglue
(t00.2 fm/c) 25/fm3
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High pT Frontier at RHIC
Four New Phenomena Discovered
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Rare Probes of Heavy Ion Collisions

• Hard pQCD Probes
• Drell-Yan
• Heavy Quarks (D, Y)
• Direct g
• Jets, high pT hadrons

Piosphere
Z

• Observables
• dE/dx in QGP ? jet quenching
• Deconfinement ? J/y suppression

beams of hard probes jets, J/y .
Jet Quenching can be used as a Tomographic
Tool
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AA Tomography with Jets
X-ray Tomography
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Jet Energy Loss and Tomography
1. GLV Formalism P.Levai, I.Vitev,MG
Non-Abelian energy loss at finite opacity,'
Nucl. Phys. B571 (2000) 197 Phys. Rev.
Lett. 85, 5535 (2000) Nucl. Phys. B594,
371 (2001) nucl-th/0112071, nucl-th/0201078
2. Flavor Tomography P.Levai, G.Papp, G.Fai,
MG, Kaon and pion ratio probes of jet
quenching '' nucl-th/0012017. The
pbargtpi- Anomaly at RHIC I.Vitev, MG
nucl-th/0104066 3. Azimuthal Tomography
I.Vitev,X.N.Wang,P.Houvonin,MG High pT
azimuthal asymmetry in non-central A A at
RHIC,'' Phys.Rev.Lett.862537 (2001)
Phys.Lett.B526301(2002 )
Baier, Dokshitzer, Mueller, Schiff 1996-
B.G.Zakharov 1996- U. Wiedemann 2000
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pQCD
Known initial flux of q and g jets
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MG, I Vitev, XN Wang, Phys.Rev.Lett.862537-2540,2
001
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Discovery Jet Quenching at RHIC
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PHENIX Phys.Rev.Lett.88022301 (2002)
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Central/Peripheral
PHENIX
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Compare to Enhancement of High pT at CERN-SPS
Pb-Pb

• RAA exhibits amplified Cronin Enhancement at SPS
  energies
• RAA (RpA ) 2
• Parton energy loss is overwhelmed
• by initial state soft multiple collisions at
  SPS!

dE/dx is small at SPS due to short plasma
lifetime and low gluon density
MG, Levai, Vitev, PRL85(00)5535
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How to extract gluon plasma density from Jet
QuenchingPattern?
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(No Transcript)
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Bjorken expansion
Asymptotic Leading Log Approx
GLV Opacity Expansion in LLA same as BDMS (mod
Log E/m2L)
Scaling Expansion
For Bjorken 11D Expansion
Transport Property
Baier, Dokshitzer, Mueller, Schiff 1996
B.G.Zakharov 2000 U. Wiedemann 2000
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GLV vs LLA
Debye screened
eff. g mass
g
g
g
and
g
g
g
LLA
Finite Ejetlt20 GeV cannot be computed in leading
log But can be computed numerically via GLV
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Predicted Quench Pattern
(GVW)
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(No Transcript)
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High pT BaryonDynamics at RHIC
Pbar gt p - for pTgt2 GeV/c ??
S.Vance,MG
Gluonic Junctions ?
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Surprise pbar gt p- at high pT???
F. Messer, PHENIX J.Velkovska, PHENIX
S.Vance,MG

• Factor 3 Quench of Pions
• Possible novel baryon (junction) dynamics at high
  pT?

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Baryon Junctions
Veneziano,Rossi
Meson
u
u
u
u
Baryon
Junction
Baryon
Junction
d
d

• Baryon transport dynamics (baryon junction) in
  rapidity y

Kharzeev

S.Vance,MG

• We also expect enhanced pT slopes for
• baryons from

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Anomalous pbars
Suppose there is a novel TB400 MeV Soft B
Component
Vitev,MG
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Charged Hadron versus Pion Quenching
PHENIX data
STAR data

• Both STAR and PHENIX data are consistent with a
  factor of 2-3 suppression
• of the high pT particle spectra.
• The difference in the suppression of and
  inclusive charged hadrons can
• be understood in a dual softhard model with
  baryon transport dynamics.
• The extracted gluon rapidity density is
  dNg/dy1000.

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Azimuthal asymmetry of high pt particles
Finite dE/dx v2(pt) 0 for pt
f
Solid cylindrical geom Dasned Wood Sax TAB
Raimond Snellings
MG, I. Vitev and X.N. Wang, PRL(01)
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pT Barrel Plot
pT
pT
4 GeV
V2 0
V2 0.2
Azimuthal Symm.
Azimuthal Asymm. At RHIC
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Summary

• Global dN/dy( s,Npart ) are consistent with
  copious gluon showers 200ltdNg/dylt1000
• Factor 3 Suppression of pTgt2GeV pions
  Tomography via Jet Quench gt dNg/dy1000
• New baryon transport dynamics revealed by
  p/p p-/p- gt1 at Dy5,
  DpT3 GeV
• Large 2 to 1 azimuthal asymmetry observed
  out to pT 6GeV!
• Need higher pT data and pA to confirm
  tomographic analysis gt rglue100 X rnuke
  reached at RHIC
• Major Puzzles
• Hydro works too well for pTlt2GeV but STAR/PHENIX
  pp HBT inconsistent with Hydro and all current
  QGP tranport models RoutRside6fm indep of
  1ltEcmlt100!
• dET/dNch independent of Ecm and Npart
• Why v2 does not decrease with pT?

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Jet quenching at RHIC (200 AGeV) versus LHC
(5400 AGeV)

• Increased quenching by a factor of
• 3 in the overlapping region
• (roughly following the density)
• Moderate pT dependence of the
• quenching factor

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Additional Effects that Influence E-Loss

• Absorption effects shown
• to be negligible for

E.Wang, X.N. Wang, PRL 87, 142301 (2001)
(E-loss with detailed balance)

• Multi-gluon fluctuations

Q is the difference between mean energy
loss and multi-gluon fluctuations tractable
M.Gyulassy, P.Levai, I.V. nucl-th/0112071
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Additional Effects that Influence E-Loss

• Include nuclear
• shadowing fa/A(x,Q2).
• Modification factor
• taken as in HIJING
• Include kT smearing and Cronin effect via
• g(k) (assumed to be Gaussian)

Same fit with Z0.4-0.5!!!