Diapositiva 1

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Rencontres QGP-France, Etretat 19 septembre 2007
Quarkonia QGP

Elena G. Ferreiro Universidad de Santiago de
Compostela Espagne
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The J/Y production An intringuing
story...
Matsui and Satz J/? destruction in a QGP by
Debye screening different states melting at
different temperatures due to different binding
energies.
SPS experimental results presented a compelling
evidence for the existence of a new state of
matter in which quarks, instead of being bound up
into more complex particles such as protons and
neutrons are liberated to roam freely.
NA50 anomalous suppression
Theoretical models at SPS w or wo QGP?
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Too many effects...
nuclear absorption
CGC
cronin effect
percolation
sequential suppresion
gluon shadowing
hadronic comovers
pomeron shadowing
recombination
partonic comovers
QGP
parton saturation
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Confusing way to distinguish the effects...
initial effects
nuclear absorption
cronin effect
CGC
.
percolation
gluon shadowing
pomeron shadowing
parton saturation
partonic comovers
final effects
QGP
hadronic comovers
sequential suppresion
recombination
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Better COLD or HOT effects
wo or w QGP
cold effects
CGC
nuclear absorption
partonic comovers
multiple scattering of a pre-resonance c-cbar
pair within the nucleons of the nucleus
percolation
hadronic comovers
parton saturation
dissociation of the c-cbar pair with the dense
medium produced in the collision partonic or
hadronic
IMP_at_SPS, NI_at_RHIC
recombination effects favoured by the high
density of partons become important and lead to
eventual saturation of the parton densities
gluon shadowing
pomeron shadowing

• suppression by a dense medium, not thermalized

nuclear structure functions in nuclei ?
superposition of constituents nucleons FKG, EKS,
pomeron CF
non thermal colour connection
recombination
IMP_at_RHIC, NI_at_SPS
hot effects
recombination
QGP
sequential suppresion
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HOT effects sequential dissociation
screening the J/? in a QGP

• J/? production
• 60 direct production J/?
• 30 via ?c? J/? x
• 10 via ?? J/? x
• Temperature of dissociation Td for ?c and ? Td
  1.1 Tc for J/? Td
  1.5 to 2 Tc

Karsch, Kharzeev, Satz, hep-ph/0512239

• Sequential dissociation as the temperature (or
  energy density) increases

SJ/? 0.6 S? 0.4 S?c
?c
?
J/?
Sequential screening of the higher
resonances that feed down the J/?
J/? itself not screened after all
Supported by recent latice calculations
Td 2 Tc
?

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HOT effects QGP, recombination
statistical coalescence model Andronic,
Braun-Muzinger,Redlich, Stachel, nucl-th/0303036

screening of primary J/y statistical
recombination of thermalized c-cbar travel of
c quarks over significant distance presence of
a deconfined phase
qgp, recom
recombination model Grandchamp, Rapp, Brown,
hep-ph/0306077
screening in-medium production includes
effects of chemical equilibrium includes
effects of thermal equilibrium
qgp, recom
movility of initally produced charm quarks in a
space-time region of color deconfinement
allows formation of heavy quarkonium states via
off-diagonal combinations of q qbar
kinetic model Thews hep-ph/0504226
qgp, recom
transport equations for the Jpsi
hydrodynamic equation for the qgp
transport in a qgp Yan, Zhuang, Xu,
nucl-th/0608010
qgp, w and wo recom
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COLD effects no QGP, recombination
suppressionrecombination in a dense medium wo
thermalization
hadron string dynamics Bratkovskaya, Kostyuk,
Cassing, Stocker, nucl-th/0402042
transport approach include backward channels
for charmonium repro duction by D
channels
full chemical equilibration not achieved in
the transport calculations
no qgp, recom
gain and loss diferential equations
for dissociation J/Ycomovers recombination
DDbar
comovers
K. Tywoniuk, I. C. Arsene, L. Bravina, A.
Kaidalov, E. Zabrodin A. Capella, E. G. Ferreiro
no qgp, recom
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The data RAA vs centrality
shadowing P -----y0,2 sabs0 shadowing EKS
Effects vraiment froids (Andry)
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The data RAA vs centrality
(Fred)
PHENIX at RHIC (ylt0.35) PHENIX at RHIC
(1.2ltylt2.2) NA50 at SPS (0ltylt1)

• Similar level of suppression
• 200 GeV AuAu _at_ ylt0.35
• 158 GeV/A PbPb _at_ 0ltylt1

• Suppression at forward rapidity greater than at
  mid-rapidity
• Observed suppression greater than initial CNM
  predictions

Bar uncorrelated error Bracket correlated
error Global error 12 and Global error 7
are not shown
shadowingnuclear absorption
vraiment froids (Andry)
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Suppression by a dense medium

• thermalized or not thermalized, this is the
  question...

no QGP
QGP
QGP
QGP
no QGP
QGP
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It doesn't matter if the medium is hot or not!

• Suppression models in agreement with SPS data
  extrapolated at RHIC
• Unmatched suppression pattern at central rapidity

w QGP
wo QGP
Dissociation by thermal gluons (R. Rapp et al.,
nucl-th/0608033 Nu Xu et al., Phys.Rev.Lett. 97
(2006) 232301)
Dissociation by comovers (Capella et al.,
hep-ph/0610313)
First problem data AuAu at central rapidity are
not reproduced (wo/w QGP)
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Regeneration, this can be the answer ...
____
Bravina y0
R. Rapp et al. PRL 92, 212301 (2004) screening
in-medium production Thews Eur. Phys. J C43, 97
(2005) statistical and kinetic model,
deconfinement recombination Nu Xu et al.
Phys.Rev.Lett. 97 (2006) 232301 transport
equations hydro recombination Bratkovskaya et
al. PRC 69, 054903 (2004) HSD, hadron-string
dynamics recombination Andronic et al.
nucl-th/0611023 SCM, screening statistical
recombination of thermalized c-cbar Bravina,
comovers suppression regeneration

• (no QGP)

(no QGP)
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some inconvenients of recombination
or not?
indetermination of scc2
it can be present w or wo thermalization -w
or wo QGP- so is not even a signal of a QGP
the results can be as bad as without
recombination
wo QGP hadronic partonic comovers
w suppressionrecombination
w QGP thermal dissociationrecombination


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Model competition
Models at SPS
AuAu mid rapidity data RHIC
Good agreement!

• ______ recombination, L.Grandchamp et al,
• PRL 92, 212301 (2004).

QGP rec

• ________ HSD, E.L.Bratkovskaya et al., PRC 71,
  044901 (2005).

no QGP rec

• ------------ SCM, A.Andronic et al.,
  nucl-th/0701079.

QGP rec

• ________ comover, A.Capella and E..Ferreiro
  hep-ph/0610313

no QGP no rec
CuCu data RHIC
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Second problem data AuAu at mid/forward
rapidity

• Opposite suppression behaviour vs rapidity

• most central collisions suppressed to 0.2
• forward suppressed more than mid-rapidity
• saturation of forward/mid suppression ratio
  rapidity _at_ 0.6 for Npart 100?
• trend opposite to that of CNM (solid lines) and
  comover (dashed) models

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Looking for solutions...
Charmed meson production in the CGC model
CGC open charm in central rapidity region at
RHIC gets suppressed as a function of rapidity
charmed meson yield gets suppressed from y0 to
y2 both in pA and AA collisions
Cause saturation scale grows with rapidity
y0
y2
Tuchin, hep-ph/0402298
?0
?2
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Lets see some results...
QGP Sequential Screening CGC
nucl-ex/0611020
nucl-ex/0611020

• QGP suppression of ?, ?C

• additional forward suppression
• from gluon saturation (CGC)

QGP
CGC

• BUT approx. flat forward/mid above
• Npart 100 seems inconsistent

• forward should drop more for
• more central collisions as
• gluon saturation increases

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QGPRegeneration

• both forward mid rapidity suppressed
• by QGP i.e. screening
• or large gluon density

nucl-ex/0611020

• mid-rapidity suppression reduced
• by strong regeneration effect

• but approx. flat forward/mid
• suppression for Npartgt100

Regen. _at_ y1.7?!
seems inconsistent with increasing regeneration
increasing QGP suppression for more central
collisions
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some innovations and predictions...
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comovers dissociation wo QGPrecombination
Tywoniuk, Arsene1, Bravina Kaidalov, Zabrodin
CRHICCLHC
CRHICCLHC gt small recomb
LHC
LHC
CRHICCLHC gt huge recomb gt enhancement
C0.8
C1.6
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SCM, Andronic, Braun-Munzinger, Riedlich,
Stachel QGPrecom
LHC
dscc/dy0.639 mb dscc/dy0.0639 mb
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comovers suppression
regeneration
SHM QGPregeneration
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if possible
CONCLUSIONS.
Why AuAu data y0 _at_ RHIC gt AuAu data y1.7 _at_
RHIC?
we need to know much better the initial CNM in
dAu
Why CuCu data _at_ RHICAuAu data _at_ RHIC for the
same Npart?
Why data _at_ RHICdata _at_ SPS for the same Npart?
to reproduce AuAu at y0
CGC
nuclear absorption
percolation
gluon shadowing
parton saturation
pomeron shadowing
QGP
partonic comovers
sequential suppression
hadronic comovers
recombination
and at y forward!
recombination
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Third problem data CuCu at mid and forward
rapidity
CuCu preliminary results follow AuAu trend vs
centrality for Npart below 100
But...
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average transverse momentum vs number of
collisions
Yan, Zhuang, Xu
R. L. Thews and M. L. Mangano
R. L. Thews and M. L. Mangano
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Summary J/? Suppression A puzzle of two (or
more) ingredients
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Refinement 3D hydro sequential dissociation
(II)

• Gunji et al., hep-ph/0703061
• Charmonia
• initial spatial distribution from collisions in
  the Glauber model
• free streaming in a full (3D1) hydro
• J/? survival probability ( RAA/CNM with CNM
  shadowing nuclear absorption sabs 1mb )
• S (1 fFD) S direct J/ ? fFD S J/???, ?c
• 3 free parameters feed-down fFD , melting
  temperatures TJ/? and T?,?c
• (3D1) hydro same setup as the one used to
  reproduce charged dN/d? measured at RHIC
• Assuming thermalization for t0.6fm, initial
  energy density distribution in the transverse
  plane, EOS of the medium (TltTc and TgtTc),

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Refinement 3D hydro sequential dissociation
(II)

• Gunji et al., hep-ph/0703061
• Charmonia
• J/? survival probability ( RAA/CNM with CNM
  shadowing nuclear absorption sabs 1mb )
• S (1 fFD) S direct J/ ? fFD S J/???, ?c
• 3 free parameters Feed-down fFD , melting
  temperatures TJ/? and T?,?c
• (3D1) hydro
• ? best fit with
• TJ/? 2.12 Tc
• T?,?c 1.34 Tc
• fFD 0.25
• 0.10 due to uncertainty
• on sabs (1 1mb)

Better matching with the data
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