Quarkonia in Medium and in Heavy-Ion Collisions

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Quarkonia in Mediumand in Heavy-Ion Collisions
Ralf Rapp Cyclotron Institute Physics
Department Texas AM University College
Station, USA Heavy-Flavor Workshop RHIC AGS
Annual Users Meeting BNL, 21.06.05
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1.Introduction The Virtue of HQs in URHICs

• Common lore , dominantly
• produced in primordial NN-collisions
• quarkonia (Ny)prim x Ncc (x1)
• ? suppression probes re-interaction
• Ncc large ? regeneration relevant
• (Ny )second (Ncc )2

PHENIX 04

• Consequences of Regeneration
• - charmonium number sensitive to open-charm
  properties
• ? masses mc, mD vs. my (thermal weights)
• ? momentum distribution (y formation)
• - Resonances in QGP?!
• quarkonia dissociation/regeneration above
  Tc
• D-mesons enhanced c-quark rescattering

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Outline
1. Introduction 2. c- and b-Quark Interactions
in Medium 2.1 Collective Flow, Coalescence
2.2 Rescattering in QGP 3. Quarkonium in Medium
3.1 Basic Elements and Connections to
URHICs 3.2 Lattice QCD and Spectral
Properties 3.3 Binding, Reaction Rates and
Equilibrium Limit 3.4 Kinetic Rate
Equation 4. Phenomenology in URHICs 4.1
J/? Suppression vs. Regeneration 4.2
Intermediate-Size Ions (A100) 4.3
Bottomonium 5. Conclusions
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2.1.1. Open-Charm and e pt-Spectra - Schematic
PYTHIA vs. ThermalFlow
D-Meson Coalescence at Tc
Greco,KoRR 04
Batsouli,Gyulassy, KellyNagle 02
PHENIX 200AGeV

• very similar on log-scale

• 3-mom. mostly in c-quark

• note RAA 0.2-0.5 for thermalization

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2.1.2. Single-e Elliptic Flow - Schematic

• Coalescence predictions
• based on same c-quark v2
• as for light quarks
• jet quenching low?

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2.2 Resonant Open-Charm Rescattering
_
_
Light-Quark Resonances
c q ? D ? c q

• effective model with pseudo/scalar
• axial/vector D-mesons

1.4Tc
Asakawa Hatsuda 03

• parameters mD(0), GD

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c-Quark Drag and Diffusion Coefficients in QGP

van HeesRR 04
Thermalization Times
pQCD
D

• resonance scatt. isotropic
• secondary open-charm ?!
• 50 for

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2.3 Bottom vs. Charm Thermalization in QGP
van HeesRR 04
Thermalization Times

• charm quark equilibration time fireball
  lifetime
• bottom quarks do not thermalize (RHIC)

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3.) Quarkonia in Medium3.1 Basic Elements and
Connections to URHICs

• 3-Stage Dissociation nuclear (pre-eq) --
  QGP -- HG
• Stot exp-snuc r L
  exp-GQGP tQGP exp-GHG tHG
• Regeneration in QGP HG
• - statistical coalescence at Tc chem.therm.
  equil.
• - more microscopically backward reaction
  (detailed balance!)

PBM etal 01, Gorenstein etal 02,
Thews etal 01, Ko etal 02, GrandchampRR
02, Cassing etal 03
for thermal c-quarks and gluons
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3.2 Lattice QCD Spectral Properties of
Charmonium

• Lattice hc, J/y survive up to 2Tc
• mass my const
• potential screened ? binding reduced
• eB 2mc - my ? mc decreases with T
• Relation to spectral function, Im Dy

Asakawa Hatsuda 03

• real part (pole ) ? screening
• imaginary part (width) ? dissociation

Datta etal 03

• microscopic origin?

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3.3.1 Quarkonium Binding Energies in QGP
e.g. screened Cornell potential (linearconfining)
Karsch,MehrSatz 88, Wong 04,
Charmonium
Bottomonium
Tc
Tc
m gT GeV
m gT GeV

• quarkonium binding energies substantially
  reduced above Tc

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3.3.2 Charmonium Reaction Rates in QGP

• (i) Gluo-
• Dissociation
• sdiss(w) peaked at w 1.4eB
• ok for free J/y (eBvac640MeV )
• not in QGP (screened), y, cc

• (ii) Quasifree
• Dissociation
• appropriate for small binding
• also involves (anti-) quarks
• neglects bound-state structure

BhanotPeskin 84
GrandchampRR 01
Cross Sections
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3.3.3 Bottomonium Reaction Rates in QGP

• screening accelerates dissociation substantially
• significance at RHIC tY 50 ? 5 fm/c

Grandchamp,Lumpkins,Sun,van HeesRR 05
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3.3.4 Charm(onium) below Tc
Hadronic dissociation
Cross Sections
Dissociation Times
QCD-SR
Mes-Ex CQM
pQCD
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3.3.5 Charmonium WidthMass from Lattice QCD
Umeda Matsufuru 05
using constrained curve fitting (Breit-Wigner
functions)
hc and J/y Width
hc and J/y Mass

• jumps across Tc
• qualitatively consistent with
• partonic dissociation

• essentially constant

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3.3.6 J/y Equilibrium Abundances
smaller mD ? smaller gc ? smaller (Ny) eq
Grandchamp, BrownRR 04

• match open-charm states continuously through Tc
• correct equil. no. for thermal relaxation R(t)
  1 - exp-? dt / tceq(T)

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3.4 Time Evolution of Quarkonia at RHIC
Solve kinetic rate-equation
J/y in Central Au-Au

• Equilibration close to Tc ?!

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4.) Charmonium in A-A
SPS
RHIC
Grandchamp RR 03
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4.1.2 J/y pt-Spectra in Au-Au at RHIC
Quark Coalescence at Tc
ThewsMangano 05
Greco,KoRR 04

• total yields different by factor 3
• large sensitivity to radial flow
  (bt,max0.5-0.65)

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4.1.3 Scrutinizing Charmonium Regeneration II
J/y Elliptic Flow
Suppression only
Thermal Coalescence at Tc
Greco etal 04
WangYuan 02
MB Au-Au

• factor 5 different!
• transition in pt!?

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4.2 Intermediate-Mass Ions
SPS
RHIC
GrandchampRR 04

• onset of regeneration

• suppression prevalent

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4.3 Upsilon at RHIC and LHC
RHIC
LHC
Grandchamp,Lumpokins,Sun,van HeesRR 05

• bottomonium suppression as unique QGP signature
  ?!

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5.) Conclusions

• Heavy Quarks in Medium
• - essential prerequisite to understand quarkonia
  in URIHCs
• - c-quarks thermalize?! (resonances?),
  b-quarks not