Vue densemble quarkonia Revue des rsultats exprimentaux SPS FNAL, HERAB RHIC, de pA AA

1
Vue densemble quarkoniaRevue des résultats
expérimentauxSPS (FNAL, HERAB) RHIC, de pA à AA

• Journées PQG France
• Étretat, 5 juillet 2006
• Raphaël Granier de Cassagnac
• LLR École polytechnique / IN2P3

2
Avertissements

• Présentation à hard probes 06
• (donc en anglais, sorry)
• Passer vite sur les points évoqués par Andry,
  Catherine, Philippe, Ermias, Paul, François,
• Pour Jean Yves, les nouveautés
  sont signalées par ce logo

3
Are we there yet ?
J/? survival probability ?
Energy density ?
4
A couple of historical facts

• In 1986, Matsui Satz predicted an unambiguous
  signature of
  QGP, that was
  immediately (1987)
  seen by NA38
  in SU collisions

Matsui Satz, PLB178 (1986) 416
NA38, NPA544 (1992) 209
5
Dabord, faites gaffe auxeffets nucléaires
froids !
6
Cold nuclear matter effects ?

• J/? (or cc) absorption
• (Anti) shadowing
• (gluon saturation, CGC)
• Energy loss of initial parton
• pT broadening (Cronin effect)
• Intrinsic charm
• Complications from feeddown ? ?c ?
• Something else ?

An example of gluon shadowing prediction
gluons in Pb / gluons in p
Anti Shadowing
Shadowing
x
Eskola, Kolhinen, Vogt NPA696 (2001) 729
7
Cold nuclear matter effects ?
A real puzzle ! Especially when one goes to low
x2, high xF
Shadowing ?
s?(pA) s?(pp) x A?
open charm
Absorption ?
dE/dx ? Intrinsic Charm ?
Voir François
xp- xA
xA
8
Nobody is perfect

• _at_SPS many pA ! High statistics ! But small
  kinematics (-0.1 lt xF lt 0.1)
• Nuclear absorption does a splendid job
• _at_FNAL less pA High statistics ! Large rapidity
  (xF) coverage No AA
• Many cold nuclear effects needed !
• _at_HERAB similar, negative xF (-0.35 to 0.15)
• _at_RHIC only dAu, low statistics, but rapidity
  (-2.2 to 2.2) and centrality dependence
• Absorption (anti)shadowing

9
Cold nuclear matter _at_ SPS

• Normal nuclear absorption does a splendid job in
  describing pA, SU, peripheral Pb-Pb
• (S-U suppression was normal)
• exp(-sabs ? L) with
• L nuclear thickness
• sabs 4,18 0,35 mb

Voir Paul
NA50, EPJ C39 (2005) 335
10
From pA to AA

• Cold nuclear matter extrapolations always rely on
  some models and pA data with various balance
  between the two
• _at_LHC, will depend strongly on models ?
• Different energies kinematics (p?A ? AA)
• _at_SPS, plug measured nuclear absorption either as
  exp(-? s L) or in Glauber model
• Is there room for (anti)shadowing ?
• Is the pA absorption applicable to AA ?
• (400 vs 158 GeV)
• Not taken care of, but again, absorption does a
  splendid job from pp to peripheral Pb-Pb

11
(Anti)shadowing _at_ SPS ?
Carlos Lourenco, Hard Probes 2006

• NA50 pA (to appear in EPJ)
• Rapidity distribution asymmetry
• From 30 to 50
• Why is there a significant change from pp to
  p-Be but not from p-Be to p-W ?
• Not that true !
• At least by the eye
• Because of shadowing ?
• Which should first depend on density, shouldnt
  it ?

50
30
12
RdAu vs Ncoll _at_ RHIC
RdA
High x2 0.09

• First centrality dependence in dA (or pA)
  measurement
• Colored lines
• FGS shadowing for 3 mb
• Black lines
• EKS98 shadowing
• sabs 0 to 3 mb
• Together with rapidity shape, this favours EKS98
  moderate absorption

Low x2 0.003
13
RdAu vs rapidity _at_ RHIC
RdA

• Data favours
• (weak) shadowing
• Eskola, Kolhinen, Salgado
• prescription matches better
• (weak) absorption
• sabs 1 to 3 mb !
• (4.18 0.35 mb _at_SPS)
• But with limited statistics difficult to
  disentangle nuclear effects !

• PHENIX, PRL96 (2006) 012304
• Klein,Vogt, PRL91 (2003) 142301
• Kopeliovich, NPA696 (2001) 669

Voir Andry
14
From dA to AA _at_ RHIC

• What is on the market ?
• First, the dA data are poor
• A model of nuclear absorption (anti)shadowing
• (Ramona Vogt, nucl-th/0507027)
• exp -(sdiss(y)sdiss(-y))n0L
• (Karsch, Kharzeev Satz PLB637(2006)75)
• sdiss from fits on dA data ?
• But shadowing doesnt go like L
• My own toy model
• (next 3 slides)

15
My own toy model (1/3)
RdA

• Data driven, as much as possible
• Phenomenological fit to RdA(b) ?
• Plug this in AuAu Glauber RAA(y,bAA)
  Scollisions RdA(-y,b1) x
  RdA (y,b2)
• Works for absorption shadowing since
  production pdf1 x pdf2 x exp ns(L1L2)

Y -1.7
Y 0
Y 1.8
b(fm)
16
My own toy model (2/3)

• Bands are statistical and systematic errors from
  dAu
• No systematic from the method itself (work in
  progress)
• Average on AuAu centrality classes to compare to
  data

17
My own toy model (3/3)

• Comparison to AuAu data and Ramonas model

18
Ensuite Cest quoi cette foutue suppression ?
19
Whats going on _at_SPS ?

• Several models could fit NA50
• Plasma (either thermal or percolative)
• Comovers (hadronic or partonic ?)
• Now NA60
• Difficult to
• reproduce

Roberta Arnaldi, QM05
Voir Paul et Philippe
20
NA60 internal comparison

• Very same data !
• What is the independent systematic uncertainty ?
• Maybe J? / DY 6 ?
• Sequential melting ?
• Only lt20 suppression ?
• Total global systematic is 11
• (8 sJ/?pp 6 DY 4 sabs)
• J/? 0.6 J/? 0.3 ?c 0.1 ? ?

Roberta Arnaldi, HP06
21
Feed down ratios ?

• From HERA-B (pA vs41.6 GeV)
• 7.0 0.4 from ?
• 21 5 from ?c
• 0.065 0.011 from B

Faccioli, Hard Probes 2006
22
Whats going on _at_ RHIC ?
voir Andry, Catherine, Ermias

• Shadowing nuclear absorption (crucial !)

-0.35 lt y lt 0.35
1.2 lt y lt 2.2
PHENIX, QM05, nucl-ex/0510051 Vogt,
nucl-th/0507027
Error bar code bars statistical, bracket
systematic, box global.
23
NA50 only effects

• Cold effects
• Comovers (hadrons or partons?)
• Kinetic model (J/? ? c c )
• Thermal plasma
• All overestimate suppression !
• So does parton percolation
• Onset at Npart 90
• Simultaneous J/? ?c ?

(AuAu only)

• Capella, Ferreiro, EPJC42 (2005) 419
• Grandchamp et al, PRL92 (2004) 212301
• Kotstyuk et al, PRC68 (2003) 041902
• Digal, Fortuno, Satz, EPJC32 (2004) 547
• Private communications

24
1st. Recombination ?

• A variety of recombination coalescence models
  can accommodate the suppression
• But early results suggest some competing
  mechanism, such as reformation of J/? particles,
  may occur at these densities. Riordan
  Zajc,
• Scientific American
• (et Pour la Science)
• To know more, look at y, pT

(AuAu only)

• Grandchamp et al, PRL92 (2004) 212301
• Bratkoskaya et al, PRC69 (2004) 054903
• Andronic et al, PLB571 (2003) 36
• Thews Mangano, PRC73 (2006) 014904c
• Private communications

25
y shape (vs recombination)

• Recombination emphasizes quark y-distribution
• Quark (open charm) y-distribution unknown
  
• No significant change in rapidity in data

Recombined only !
? Thews Mangano, PRC73 (2006) 014904c
26
ltpT2gt (vs Cronin effect)

• ltpT2gtAA ltpT2gtpp ? ? ?pT2 x L nuclear matter
  thickness
• (random walk of initial gluons)

Lower energy survey pp, pA and AA
VN Tram, Moriond 2006 PhD thesis
27
Cronin versus recombination

• At forward rapidity (closed symbols)
• from pp dA
• ltpT2gt 2.51 0.32 L
• (L lt-gt Ncoll conversion)
• No sign of recombination !
• At mid rapidity (open symbols)
• Negligible Cronin !?...
• Need better pp !

pp dAu AuAu
ltpT2gt 2.51 0.32 L
Open symbol y 0 Full curves y 2
VN Tram, Moriond 2006 PhD thesis Thews
Mangano, PRC73 (2006) 014904c
28
2nd. Hydro J/? transport

• One detailed QGP hydro J/? transport (Zhu et
  al)
• g J/? ? c c
• First published without cold nuclear effects, but
  here
• Nuclear absorption (1 or 3 mb)
• Cronin effect from dAu
• ltpT2gt ok (as on previous slide)
• Model should be valid for y0
• But match y1.7
• (and central y0)

Predicted RAA for y0
Zhu, Zhuang, Xu, PLB607 (2005) 107 private
communication
29
3rd (simple) explanation

• Amount of anomalous suppression depends on cold
  nuclear effects amplitude
• But could be as low as 30 to 40
• Compatible to feed-down ratio
• J/? 0.6 J/? 0.3 ?c 0.1 ?
• Recent lattice Td? 1.5 - 2.5 Tc
• e x (TdJ/? 2Tc)4 2 ec
  edJ/? 32 ec !
• Wait for LHC to melt J/? ?

30
Back to SPS RHIC

• Sequential melting scenario
• J/? survival only
• Excited states melting from ? suppression
  pattern _at_ SPS
• But J/? stay while ? leave in S-U
• Be careful when showing this!
• NA60 and PHENIX are PRELMINARY
• No systematic uncertainties on PHENIX (and NA60)
  points
• No uncertainties from cold nuclear matter effects
  !
• However, it does a good job and sequential
  melting clearly is a possibility !...

???
Karsch, Kharzeev Satz PLB637(2006)75
31
Et maintenant, peut-on se ploter tous ensemble ?
32
x-axis energy density ?

• Should be the right variable
• But we dont really know how to compare RHIC
  SPS!
• Relevant time should be the J/? formation time,
  SPS RHIC !
• But SPS violate the pancake hypothesis (nuclei
  take 1.6 fm/c to cross each other)
• ??0 lt 1 fm/c _at_ RHIC
• (formation time 0.35 ?)

All RHIC
All SPS
33
Thats it for today
PHENIX for 1mb absorption shadowing
PHENIX for 3mb absorption shadowing
(global SPS uncertainty not included)
NA60 new points from Roberta Arnaldi
34
Anomalous conclusions

• For now, no model to explain NA60
• But sequential melting ?
• For now, 3 models to explain RHIC
• 1st Recombination ?
• But no sign of y or pT2 modifications
• J/? ? (Ncc)2 (but how much is Ncc ?)
• 2nd J/? detailed transport in hydro QGP
• 3rd Sequential melting ?
• J/? may still survive _at_ RHIC
• (this three models assume a QGP)

35
The show must go on

• What is coming from SPS ?
• J/? flow (Cf. Francesco Prino HP06)
• ? from InIn ? ?c from pA ?
• J/? pA _at_ 158 AGeV
• What is coming from RHIC ?
• Final AA analysis
• A bit more data more bins !
• With a better pp ref (run 5)
• With J/? elliptic flow ? ?
• First look at ?, ?c and upsilons
• Going on with run 5 pp
• STAR entering the game
• What is needed at RHIC ?
• More dA ! Better handle cold nuclear effects
• More AA ! With open charm, ?,
• Better open charm measurements (SiVTX upgrades
  ?

Zhu, Zhuang, Xu, PLB607 (2005) 107
36
Shadowing, absorption
Recombination
Excited states
Direct ?
This world may not exist
37
Back-up slides
38
? versus energy density
Louis Kluberg _at_ Satz fest !
39
Two words on ?

• To answer Philippe
• ? ed? 0.8 GeV/fm2
• ? ?c ed? 2 GeV/fm2
• T(?c)/T(?) 1.25 !
• To answer Louis (KKS)
• So far we have considered only symmetric (A-A)
  collisions. We find, however, that the ?'
  production measured in S-U interactions at the
  SPS 28 also agrees quite well with the pattern
  shown

This is not energy density But it approximately
works too (Louis_at_Satz anniversary)
40
b) Nuclear absorption _at_ SPS

• Expected 4.18 mb absorption
• (works from pp to PbPb periph)
• while ?vus 0.6 ? 0.3 ?c 0.1 ?
• and sabs (?) 7.9 0.6 mb

• Here, I imagine an extreme scenario
  instantaneous melting
• L7.0 fm in PbPb L6.2 fm in InIn
• sabs(?c) sabs(?) ? sabs(?) 2 mb

An upper bound
(results shown by NA60)
41
A bit more on excited states
Faccioli, Hard Probes 2006

• Some news from HERA-B
• 7.0 0.4 from ?
• 21 5 from ?c
• 0.065 0.011 from B

• sabs(?) 2.9 mb
• Survival 70
• Consistency

42
Some more HERA-B points
43
RAA versus Ncoll
Hugo Pereira da Costa, for PHENIX, QM05,
nucl-ex/0510051
44
Deuteron ? ? Gold

• In PHENIX, J/? mostly produced by gluon fusion,
  and thus sensitive to gluon pdf
• Three rapidity ranges probe different momentum
  fraction of Au partons
• South (y lt -1.2) large x2 (in gold) 0.090
• Central (y 0) intermediate x2 0.020
• North (y gt 1.2) small x2 (in gold) 0.003

d
Au
45
Quick look to open charm

• Through semileptonic decays (D ? e)

25 systematic uncertainties (without Silicon
vertex detector upgrade)
PHENIX, PRL94 (2005) 082301
46
Charm quench flow
47
Na50/Phenix comparisons
PHENIX expected
PHENIX expected
1mb
1mb
NA50 expected 4.18mb
NA50 expected 4.18 mb
3mb
3mb
Consistent suppression amplitude observed but
cold nuclear effects may be different
48
measured/expected vs ?Bj
(x ?0) !
?abs 3 mb
?abs 1 mb
Below unity ! Suppression amplitude consistent
within error bars
49
measured/expected vs Npart
?abs 3 mb
?abs 1 mb
Under unity Larger difference when 1mb but
compatible within error bars
50
recombination/suppression
51
ltpT2gt (vs recombination)
Robert Thews, SQM06
52
Cronin effect
Scattering of initial gluons of nucleon before
ccbar formation random walk ltpt2gtAA ltpt2gtpp
???(ltpt2gt) LAA

v s 17.3 GeV NA50/60 PbPb, InIn v s 19.4
GeV NA3 pp, NA38 pCu, pU,OU, SU v s
27.4 GeV NA50 pBe, pAl, pCu, pW v s 29.1
GeV NA51 pp, pd, NA50 pAl, pW v s 38.8
GeV E866/789/771

• nuclear density, ? elastic gluon-nucleon
  scattering cross section, ?(ltpt2gt)
• kick given by each scattering and L average
  thickness of nuclear matter

53
Cronin effect
Cronin ltpt2gtAA ltpt2gtpp ???(ltpt2gt) LAA

Extrapolation curve from PHENIX J/? results in
pp and dAu
54
Cronin effect
Cronin ltpt2gtAA ltpt2gtpp ???(ltpt2gt)
LAA Extrapolation curve from PHENIX J/? results
in pp and dAu

pp dAu AuAu
At forward rapidity, ltpt2gt variation compatible
with this Cronin extrapolation At mid rapidity,
measurements in pp and dAu indicate a weak
Cronin effect
55
A busy plot about ltpT2gt

• ( curves to be compared with AA _at_ 1.2ltylt2.2 )

56
Rapidity width
Width pp 1.75 ? 0.21
No noticeable change in rapidity width
VN Tram thesis
57
More on transport model

• 21D hydro
• Boltzman-type transport
• Local equilibrium
• (0.8 0.6 fm/c)
• Normal to anomalous
• Tc 165 MeV
• Tfo 60 MeV
• g? ? cc
• 40 feeddown
• No in-medium mod.
• No absorption _at_RHIC (here)

Zhu, Zhuang, Xu, PLB607 (2005) 107
58
First upsilons

• Run 5 pp (3 pb-1)

Hie Wei, Quark Matter 2005
59
Centrality analysis

• Au breaks up in our south beam counter
• Define 4 centrality classes
• Relate centrality to ltNcollgt
• through Glauber computation
• ltNcollgt 8.4 0.7

ltNcollgt 3.2 0.3
Counts
Peripheral
ltNcollgt 15.0 1.0
Central
MB
South BBC Charge
60
Centrality analysis

• BBC charge versus ZDC energy

Most central 0 - 5 lt Npart gt 351 2.9 lt
Ncoll gt 1065 105
Most peripheral 80 92.2 lt Npart gt 6.3
1.2 lt Ncoll gt 4.9 1.2
61
Cross section versus pT
?ltpT2gt ltpT2gtdAu ltpT2gtpp Backward 1.77
0.37 GeV 2 Mid (-1.28 0.94 GeV 2 ) Forward
1.12 0.35 GeV 2
PHENIX, PRL96 (2006) 012304

• Some pT broadening

62
Dielectron pp and dA
63
RdAu versus pT
RdA
High x2
Low x2

• Broadening comparable to lower energy (?s
  39 GeV in E866)

64
Cross section vs rapidity

• Total cross section
• ? (pp ? J/?)
• 2.61 0.20 0.26 µb
• Error from fit (incl. syst and stat)
• Error on absolute normalization

PHENIX, PRL96 (2006) 012304
65
Cross section versus pT

• Fit the function
• ltpT2gt 2.51 0.21
• ( GeV2 )

PHENIX, PRL96 (2006) 012304
66
pp perspectives

• Production mechanism
• Color Octet Model does the job
• In AA (or dA)
• Large combinatorial background
• Low physics background
• (Drell-Yan or dileptons from open charm)
• pp is our baseline
• Nuclear modification factor
• Run5 pp analysis going on
• gt 10 times statistics

PRL96, 012304 (2006)
67
NA50 versus NA60 (QM05)
No overlap
Good agreement !
68
? versus X compared to lower ?s

• E866, PRL 84, (2000) 3256 NA3, ZP C20, (1983)
  101
• PHENIX, PRL96 (2006) 012304

XF Xd - XAu
X2 (in gold)

• Not universal versus X2 shadowing is not the
  whole story.
• Same versus XF for diff ?s. Incident parton
  energy loss ? (high Xd high XF)
• Energy loss expected to be weak at RHIC energy.

69
How to get xF scaling ?
70
Naive picture

• Less absorption
• Shadowing
• Energy loss

(Kopeliovich)
71
Tuchin Kharzeev

• Hard probes 2004
• hep-ph/0504133
• Coherent production of charm (open or closed)
• (ylt0 production time to low to make computation)
• Shadowing from CGC computation

72
Tuchin Kharzeev

• absorption for
• SPS fermilab

73
goldgold extrapolation