Charmonium suppression by thermal dissociation and percolation
-
Upload
kane-burton -
Category
Documents
-
view
33 -
download
2
description
Transcript of Charmonium suppression by thermal dissociation and percolation
![Page 1: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/1.jpg)
Marzia NardiCERN – TH
Marzia NardiCERN – TH
Hard Probes ‘04Hard Probes ‘04 Ericeira, Nov. 4-10, 2004 Hard Probes ‘04Hard Probes ‘04 Ericeira, Nov. 4-10, 2004
Charmonium suppression by
thermal dissociation and
percolation
Charmonium suppression by
thermal dissociation and
percolation
![Page 2: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/2.jpg)
general remarks
![Page 3: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/3.jpg)
Hard Probes ‘04 Marzia Nardi 4
general remarks
Charmonium (bottomonium) spettroscopy is well reproduced by simple NR model §
by solving the Schroedinger equation with the
Cornell potential :
§ Jacobs et al. Phys. Rev. D 33 (1986) 3338; Eichten et al. Phys. Rev. D 52 (1995) 1726.
rr
arV )(
• rJ/~ 0.2 fm (hadron : r ~ 1 fm)
• E = 2MD-2MJ/
r
V
![Page 4: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/4.jpg)
Hard Probes ‘04 Marzia Nardi 5
general remarks
Only a fraction of the observed J/’s are directly produced. The rest come from the decay of higher excited states.
The feed-down has been studied in p-N and -N interactions. J/
’
J/
J/
![Page 5: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/5.jpg)
Hard Probes ‘04 Marzia Nardi 6
general remarks
![Page 6: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/6.jpg)
Hard Probes ‘04 Marzia Nardi 7
general remarks
J/
J/
J/
J/ J/
J/
’
’
![Page 7: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/7.jpg)
Hard Probes ‘04 Marzia Nardi 8
general remarks
J/
J/
J/
J/ J/
J/
’
’
J/
J/
J/
J/…
…
…
…
…
![Page 8: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/8.jpg)
Hard Probes ‘04 Marzia Nardi 9
general remarks
J/
J/
J/
J/ J/
J/
![Page 9: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/9.jpg)
Hard Probes ‘04 Marzia Nardi 10
general remarks
The medium (confined / deconfined) affects differently the different charmonium states.
Different properties (binding energy, size,…) implies different dissociation temperatures or different cross-sections for interactions with hadrons.
dirdirdirJJ SSSS '// 1.03.06.0
![Page 10: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/10.jpg)
thermal dissociation
![Page 11: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/11.jpg)
Hard Probes ‘04 Marzia Nardi 12
thermal dissociation The heavy quark potential at high T can be obtained with lattice QCD calculation:
-T ln <L(0)L+(r)> = V(T,r)-TS + C
De Tar et al., Phys.Rev.D59(‘99) 03150; Karsch et al.,Nucl.Phys.B605 (‘01) 579
![Page 12: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/12.jpg)
Hard Probes ‘04 Marzia Nardi 13
thermal dissociation
Above Tc (170 MeV for 2+1 flavor QCD) :
The interaction vanishes for r > r0(T)
[Digal et al., hep-ph/0110406; Phys.Rev.D64 ( 2001) 094015]
![Page 13: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/13.jpg)
Hard Probes ‘04 Marzia Nardi 14
thermal dissociation
Above Tc
results: Mi(T) , ri(T)
No bound state if
ri(T)>r0(T)
iiim MrTVm )],(2[ 121
J/dissolves at T ~ 1.1 Tc
![Page 14: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/14.jpg)
Hard Probes ‘04 Marzia Nardi 16
thermal dissociationBelow Tc :
The bound state exists only for )()( TVTM i
![Page 15: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/15.jpg)
Hard Probes ‘04 Marzia Nardi 17
thermal dissociation
’ dissociate at T ~ 0.2 Tc
dissociate at T ~ 0.75 Tc
![Page 16: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/16.jpg)
Hard Probes ‘04 Marzia Nardi 18
thermal dissociationJ/ suppression pattern
’
direct J/
![Page 17: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/17.jpg)
Hard Probes ‘04 Marzia Nardi 19
thermal dissociation
Results for bottomonium :
![Page 18: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/18.jpg)
Hard Probes ‘04 Marzia Nardi 20
thermal dissociation suppression pattern
2 % (3s)
10 % (2P)
10 % (2s)
26 % (1P)
52 % (1s) dir.
![Page 19: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/19.jpg)
Hard Probes ‘04 Marzia Nardi 21
thermal dissociation
Warning :Recent lattice calculations ‡ found:
‡ Datta et al., hep-lat/0312037 ; hep-lat/0403017; Asakawa et al. hep-lat/0308034 ¶ Datta et al., hep-lat/0409147
cdiss
J
cdissdiss
TT
TTT
)25.1(
1.1
/
'
•The threshold is lowered if the relative momentum is taken into account ¶.
•T dependence of the width ?
![Page 20: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/20.jpg)
percolation
![Page 21: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/21.jpg)
Hard Probes ‘04 Marzia Nardi 23
percolation
• critical phenomenon
• pre-equilibrium deconfinement
• prerequisite for QGP
• finite system, continuum
First works: Baym , Physica (Amsterdam) 96A, 131 (1979)Celik et al., Phys. Lett. 97B (1980) 128
![Page 22: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/22.jpg)
Hard Probes ‘04 Marzia Nardi 24
percolationCircular surface of radius R and N small discs of radius r<<R randomly distributed.
R
The cluster size increase with increasing n=N/R2
s
n
![Page 23: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/23.jpg)
Hard Probes ‘04 Marzia Nardi 25
percolation
Continuum percolation
Scl ~ (nc-n)–
infinite system
finite system
Scl
nc
![Page 24: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/24.jpg)
Hard Probes ‘04 Marzia Nardi 26
percolation
Cluster formation shows critical behaviour:
in the limit of infinite R and N with constant n
the cluster size diverges at a critical density nc.
Onset of percolation :
)(
/ 2
nnS
rn
ccl
cc
with = 43/18 ; c~1.12-1.13
![Page 25: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/25.jpg)
Hard Probes ‘04 Marzia Nardi 27
percolation
J/ suppression in percolation models:• Santiago Model: Armesto et al.,
Phys.Rev.Lett. 77 (1996) 3736; Ferreiro et at. Hep-ph/0107319.
• Bielefeld Model: Nardi et al. Phys. Lett. B442 (1998) 14; Digal et al., Phys.Lett. B549 (2002) 101; Digal et al., EPJ C32 (2004) 547.
• Lisbon Model: Dias de Deus et al., EPJ C16 (2000) 537; Ugoccioni et al. Nucl.Phys. B92 (2001) 83.
![Page 26: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/26.jpg)
Hard Probes ‘04 Marzia Nardi 28
percolation
Santiago Model• Color strings are exchanged between interacting hadrons.
• The number of strings grows with energy and with the number of partecipating nucleons in nuclear collisions.
•When the density of strings becomes high, some of them fuse.
![Page 27: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/27.jpg)
Hard Probes ‘04 Marzia Nardi 29
percolation
• The regions where several strings fuse is a droplet of non-thermalized QGP.• At the percolation onset the QGP domain becomes comparable to the nuclear size.• The parameters of the model (transverse size of a string, number of fusing strings) are determined by fitting the anti-rapidity distribution in S-S, S-Ag, Pb-Pb.
– r = 0.2 fm = transverse radius of a string
– nc = 9 strings/fm2
![Page 28: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/28.jpg)
Hard Probes ‘04 Marzia Nardi 30
percolation
nc = 9 fm-2
At SPS energies the percolation
threshold is between
central S-U and central
Pb-Pb
![Page 29: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/29.jpg)
Hard Probes ‘04 Marzia Nardi 31
Bielefeld model:The transverse size rcof the percolating par-tons is determined by the condition (Qc=1/rc) :
the density of the largest cluster at the per-colation point is :
with c=1.72 (local percolation condition)
percolation
![Page 30: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/30.jpg)
Hard Probes ‘04 Marzia Nardi 34
percolation For realistic nuclei the initial parton distribution is given by nuclear density profile (Fermi distrib.).
c, c : same as for uniform distribution.Qc~ 0.7 GeV, Npart = 125 (b ~ 8fm)
Q()~0.6 GeVQ(’)~ 0.5 GeVand ’ are dissociated at the percolation (onset
of deconfinement).
Directly produced J/’s survive because
Q(J/)~1GeV; second threshold at
Npart=200-300
![Page 31: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/31.jpg)
Hard Probes ‘04 Marzia Nardi 36
percolation
Results :(including Npart-b fuctuations)
Data: NA50 Coll.
Pb-Pb collisions at
SPS
![Page 32: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/32.jpg)
Hard Probes ‘04 Marzia Nardi 37
percolation
Results :(including Npart-b fuctuations)
S-U collisions
at SPS
![Page 33: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/33.jpg)
Hard Probes ‘04 Marzia Nardi 38
percolation
Predictions:
In-In collisions at SPS (NA60)
![Page 34: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/34.jpg)
Hard Probes ‘04 Marzia Nardi 39
percolation
Predictions:
Au-Au collisions at
RHICCommon onset for all charmonium states !
![Page 35: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/35.jpg)
Hard Probes ‘04 Marzia Nardi 40
Percolation orthermal dissociation ?
Thermal dissociation Percolation
Au-Au collisions at RHIC
hadronic interactions : gradual suppression
![Page 36: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/36.jpg)
Hard Probes ‘04 Marzia Nardi 41
percolation
Lisbon Model:•Framework of a multicollisional model.•String absorption and fusion: J/suppression,multiplicity distribution, ET distribution
•Number of string ∝ number of collisions; r=0.2fm
)(
2)(
1)(
exp}exp{
2
1//
S
aL
s
cs
pp
DY
J
AA
DY
J
![Page 37: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/37.jpg)
Hard Probes ‘04 Marzia Nardi 42
![Page 38: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/38.jpg)
conclusions
![Page 39: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/39.jpg)
Hard Probes ‘04 Marzia Nardi 46
conclusions
• Present experimental data do not allow to distinguish between the two scenarios. Future experiments will help.
• Progress to extend the percolation approach to different observables.
![Page 40: Charmonium suppression by thermal dissociation and percolation](https://reader035.fdocuments.us/reader035/viewer/2022062517/568138ff550346895da0b7d7/html5/thumbnails/40.jpg)
Hard Probes ‘04 Marzia Nardi 47
percolation
Continuum percolation
Scl ~ (nc-n)–
infinite system
finite system
Scl
nc