Experimental Status of J/Experimental Status of J/ψ ψ measurementsmeasurementsin in nucleusnucleus--nucleusnucleus collisionscollisions

A. A. MarínMarín

IndexIndex

Introduction: J/ψ properties, discoveryExperimental results: SPS, RHICOutlook: v2, LHC

J/J/ψψ propertiesproperties (PDG2006)(PDG2006)

J/ψ (1S)

m = 3096.916 +- 0.011 MeVΓ = 93.4 +- 2.1 KeV

decays: BR(e+e-) = (5.94 +- 0.06)%BR(µ +µ-) = (5.93 +- 0.06) %hadrons: 87.7 %

J/J/ψψ discoverydiscovery ( 1974)( 1974)

e+e- hadrons

e+e- e+e-

e+e- µ+µ−,π+π−,K+ K-

p+Be e+e- X

J. J. Aubert et al., Phys. Rev. Lett. 33 (1974) 1404J.-E. Augustin et al., Phys. Rev. Lett. 33 (1974) 1406

QuarkoniaQuarkonia

20 years ago: Matsui & Satz ( Phys. Lett. B178(1986) 416 )

color screening in deconfined matter → J/ψ suppression = “smoking gun”

experimental & theoretical progress since then → story is much more complicated

cold nuclear matter / initial state effects“normal” absorption in cold matter(anti)shadowingsaturation, color glass condensate

suppression via comoversfeed down from χc, ψ’sequential screening (first: χc, ψ’, J/ψ only well above Tc)regeneration via statistical hadronization or charm coalescence

relevant for “large” charm yield, i.e. RHIC and LHC

Main Experimental results Main Experimental results SPS

NA38, NA50:Phys. Lett. B 270 (1991) 105 (0+Cu,O+U)Phys. Lett. B 410 (1997) 327, 337 (Pb+Pb)Phys. Lett. B 438 (1998) 35 (pp,pd)Phys. Lett. B 444 (1998) 516 (p+C,p+Al,p+Cu,p+W)Phys. Lett. B 449 (1998) 128 (S+U)Phys. Lett. B 450 (1999) 456Phys. Lett. B 466 (1999) 408 Phys. Lett. B 477 (2000) 28Phys. Lett. B 499 (2001) 85Phys. Lett. B 521 (2001) 195Eur. Phys. J. C 33 (2004) 31Eur. Phys. J. C 39 (2005) 335 (Pb+Pb) (...)

NA60: Phys. Rev. Lett. 99 (2007) 132302 (In+In) (...)

RHICPHENIX:

Phys. Rev. Lett. 92 (2004) 051802 (p+p)Phys. Rev. Lett. 96 (2006) 012304 (d+Au , p+p), nucl-ex/0711.3971v1Phys. Rev. Lett. 98 (2007) 232002 (p+p)Phys. Rev. Lett. 98 (2007) 232301 (Au+Au)nucl-ex/0801.0220v1 (Cu+Cu) (...)

NA50 NA50 experimentexperiment

(J/(J/ψψ)/DY@158 GeV)/DY@158 GeV ((NA50): NA50): EurEur. Phys. J. C 39(2005) 335. Phys. J. C 39(2005) 335

Departure from normal nuclear absorption curve for central collisions

Multistep fit to extract the 4 signalcontributions:

J/ψ , ψ',Drell-Yan, Open charm

Results from pResults from p--A and PbA and Pb--PbPb

exp(-σabs ρ0L)

• Absorption in cold nuclear matter (p-A) can explain S-U data• Anomalous suppression sets in for semi-peripheral Pb-Pb collisions

• But• p-A data taken in a different energy/kinematic range• Is there anomalous suppression for systems lighter than Pb-Pb ?

Capella, SousaEPJ C30, 117 (2003)

Capella, Ferreirohep-ph/0505032

Digal, Fortunato, Satzhep-ph/0310354

Grandchamp, Rapp, Brownhep-ph/0306077

regeneration

direct

QGP sequential screening

comovers

Models without regeneration

total

J/ψψ’,χ

Models that reproduce NA50 results : • Satz - color screening in QGP (percolation model) with CNM added (EKS shadowing + 1 mb)• Capella – comovers with normal absorption and shadowing• Rapp – direct production with CNM effects (without regeneration)

NA60 NA60 experimentexperiment

hadron absorberMuonOther

and trackingMuon triggerm

agnetic field

Iron wall

NA10/38/50 spectrometer2.5 T dipole magnet

Matching in coordinate and momentum space

targets

beam tracker

vertex tracker

ZDC

NA60 NA60 @158 GeV@158 GeV In+In: In+In: PRL 99 (2007) 132302PRL 99 (2007) 132302

• Obtain ratio of charmonia production to Drell-Yan(à la NA50)

• Kinematic region• 0 < yCM <1• -0.5 < cos θCS < 0.5

• Acceptances• J/ψ : 0.156• ψ’ : 0.173• DY (2.9<mµµ<4.5) : 0.150

Results and systematic errorsResults and systematic errorsSmall statistical errors

Careful study of systematicerrors is needed

• Sources• Uncertainty on normal

nuclear absorption parameters(σabs(J/ψ) and σpp(J/ψ))

• Uncertainty on relative normalization between data and absorption curve

• Uncertainty on centrality determination (affects relative position of data and abs. curve)

• Glauber model parameters• EZDC to Npart

• ~10% error centrality indep.→ does not affect shape of the distribution• Partly common to analyses a and b• (Most) Central points affected by a considerable error

Comparison with previous results (vs NComparison with previous results (vs Npartpart))

• NA50: Npart estimated through ET (left), or EZDC (right, as in NA60)

• Good agreement is observed

(J/(J/ψψ)/DY at 158 GeV)/DY at 158 GeV

( )( ) 0.081.03

σσB

σσBextrap GeV, (400) 450

LDYJ/ψµµ

meas GeV, 158 LDYJ/ψµµ

±=⟩⟨

⟩⟨

⟨(J/ψ)/DY⟩ = 29.2 ± 2.3⟨L⟩ = 3.4 fm

Preliminary!

Rescaled to 158 GeV

exp(-σabs ρ0L)

• Preliminary NA60 result shows that the rescaling of the J/ψproduction cross section from 450(400) GeV to 158 GeV is correct !

Transverse momentum distributionsTransverse momentum distributions

Kinematical region0.1 < yCM < 0.9

-0.4 < cosθH < 0.4

Transverse momentum distributions fitted with

Tm

TT

TedpdN

p1 −=

• Study evolution ofT and ⟨pT

2⟩ withcentrality

⟨⟨ppTT22⟩⟩ vs centrality vs centrality

• If pT broadening is due to gluon scattering in the initial state→ ⟨pT

2⟩ = ⟨pT2⟩pp + αgN · L

αgNInIn = 0.067 ± 0.011 (GeV/c)2/fm

⟨pT2⟩pp

InIn = 1.15 ± 0.07 (GeV/c)2

χ2/ndf = 0.62

αgNPbPb = 0.073 ± 0.005 (GeV/c)2/fm

⟨pT2⟩pp

PbPb = 1.19 ± 0.04 (GeV/c)2

χ2/ndf = 1.22

• NA60 In-In points are in fairagreement with Pb-Pb results

• We get

to be compared with

(NA50 2000 event sample)

T vs centralityT vs centrality

Fitting functions• Used by NA50• Gives slightly

higher T values (~ 7 MeV)1) dN/dpT = pT mT K1(mT/T)

2) dN/dpT = pT e -mT/T

J/J/ψψ rapidity distributionsrapidity distributions

σy = 0.68 ± 0.02χ2/ndf = 0.60

0<pT<5, -0.4 < cosθH < 0.4

• Data are consistent with a gaussianrapidity distribution

• Centrality independent• Slightly narrower at high pT ?

Azimuthal distribution of the J/Azimuthal distribution of the J/ψψcentral peripheral

More peripheral data hint for a non isotropic emission pattern?

Only 50% of the statistics analyzed

Comparison with theoretical predictionsComparison with theoretical predictions

centrality dependent τ0

fixed termalization time τ0

A. Capella, E. Ferreiro EPJ C42(2005) 419

R.Rapp, EPJ C43(2005) 91

S. Digal, S. Fortunato, H. Satz, EPJ C32(2004) 547

Dissociation andregeneration in QGPand hadron gas

Percolation, withonset of suppression at Npart~140

Suppression by hadroniccomovers (σco = 0.65 mb,tuned for Pb-Pb collisions)

• Size of the anomalous suppression reasonably reproduced• Quantitative description not satisfactory

J/J/ψψ Production from the PHENIX Production from the PHENIX Experiment@RHICExperiment@RHIC

PHENIX DetectorPHENIX Detector

J/ψ → e+ e-

p > 0.2GeV/c|η| < 0.35

∆φ = π

J/ψ → µ+ µ-

p > 2GeV/c1.2 < |y| < 2.2

∆φ = 2π

Signal ExtractionSignal Extraction

Event MixedBackgroundSubtraction

PHENIXp+p 200GeV

hep-ex/0611020

Like SignSubtraction

hep-ex/0611020

Mid-Rapidity: |y| < 0.35

Forward Rapidity: 1.2< |y| <2.2

Mass plotsMass plots

Run-2 p+pee

Run-2 Au+Auee

Run-3 d+Auee

Run-3 p+pee

Run-5 p+pee

Run-4 Au+Auee

Run-5 Cu+Cuee

Run-2 p+pµµ

Run-3 p+pµµ

Run-5 p+pµµ

Run-3 d+Auµµ

Run-4 Au+Auµµ

Run-5 Cu+Cuµµ

J/ψ mass : 3.097 GeV/c2

J/ψ e+e- : BR 5.94 +/- 0.06 %J/ψ µ+µ- : BR 5.93 +/- 0.06 %

Measured ~30k J/ψ by Run-5.

J/J/ψψ Production in p+p CollisionsProduction in p+p Collisions

f ( pT ) = p0 1+pT

p1

⎛

⎝ ⎜

⎞

⎠ ⎟

2⎡

⎣ ⎢ ⎢

⎤

⎦ ⎥ ⎥

−6

or from data

3.5 pb-1, 2.7 pb-1,2.6 pb-1

• pT spectrum mapped from 0-9 GeV/c• Ratio of pT distributions shows a

softening at forward rapidity PRL 98 (2007) 232002

J/J/ψψ Cross Section Model ComparisonsCross Section Model Comparisons

Comparison with theory allows differentiation among the available J/ψ production mechanismsMany calculations are inconsistent with the steepness of the slope at forward rapidity and the slight flattening observed at mid-rapidity PHENIX acceptance covers 92% of integrated cross section

Bll* σpp(J/ψ )=178±3± 53 ± 18 nb

J/J/ψψ Production in Production in Au+AuAu+Au CollisionsCollisions

157 µb-1, 174 µb-1

•Shape of rapidity dependence of J/ψ yield narrows slightly as a function of centrality

•No difference observed between peripheral Au+Au and p+p distributions

•Sharp rapidity narrowing predicted byrecombination models not present

J/J/ψψ Production in Production in Au+AuAu+Au CollisionsCollisions

RAB =Nψ

AB

NψPP <Ncoll>x

RAA-pT of model predictions?Flat RAA for Npart <100

RRAAAA--rapidityrapidity Au+Au data

CNM 0mb

3mbFlat RAA for Npart<100. Rapidity narrowing in central Au+Au collisions

(Modest) Recombination?Nrec

J/ψ α Nc2

Color Glass Condensate?Measurement of J/ψ elliptic flow can make clear the origin of rapidity narrowing.

SCMFull recombination

CNM : R. Vogt Acta Phys. Hung. A25 (2006) 97.SCM : A.Andronic et al., nucl-th/0701079. Full recombination : R.L.Thews and M.L.Mangano, PRC73 (2006) 014904.

J/J/ψψ at RHIC: Rat RHIC: RAA AA vsvs NNPART PART yy--dependencedependencep+p ref. and Au+Au data → rapidity and pT spectra challenge for

production models more suppression at forward rapidity!

opposite to trend from co-mover or CNM absorption

– more co-movers at y~0suppression not only driven by local particle densitymore regeneration at y~0?gluon saturation at forward y?

modelsno clear picture yet, but important new constraintstwo (or more) ingredients needed to describe suppression pattern

– suppression + regeneration– sequential dissociation + saturation

Direct comparison to SPSDirect comparison to SPSJ/ψ were also measured in HICs at SPS

S+U (NA38), Pb+Pb (NA50) and In+In (NA60), fixed target (√sNN ~ 20GeV)Comparing RHIC and SPS is delicate

Factoring out CNM effects (not same at SPS/RHIC)

RAA (y~0) ~ RAA (SPS)Not what’s expected from√sNN,SPS < √sNN,RHIC

Rapidity ranges not same0 < ysps < 1

Big error bars on RHIC data points~10% normalization error at SPS

Err. Glo = 7%Err. Glo = 12%

Scomparin (proc. QM06) : nucl-ex/0703030

Capella, SousaEPJ C30, 117 (2003)

Capella, Ferreirohep-ph/0505032

Digal, Fortunato, Satzhep-ph/0310354

Grandchamp, Rapp, Brownhep-ph/0306077

regeneration

Models that reproduce NA50 results at lower energies (above): • Satz - color screening in QGP (percolation model) with CNM added (EKS shadowing + 1 mb)• Capella – comovers with normal absorption and shadowing• Rapp – direct production with CNM effects (without regeneration)But predict too much suppression for RHIC mid-rapidity (at right)!

direct

QGP sequential screening

comovers

Models without regeneration

total

J/ψψ’,χ

nucl-ex/0611020

RappCapella

Satz

J/ψ,ψ’,χc

All models for y=0

Satz

RappCapella

J/ψ,ψ’,χc

All models for y=0 nucl-ex/0611020

StatisticalStatistical HadronizationHadronization Model Model (PLB 652 (2007) 259)(PLB 652 (2007) 259)

Clear signal for generation of charmonia due to statistical hadronization at the phase boundary

J/J/ψψ Production in Production in d+Aud+Au CollisionsCollisions nuclnucl--exex/0711.3917v1/0711.3917v1

1.4nb-1, 1.7 nb-1

New and oldanalysis arecompatible

J/J/ψψ in in d+Aud+Au: Cold : Cold NuclearNuclear matter matter effectseffects

Statisticallysignificant suppression

J/J/ψψ in in d+Aud+Au: : ComparisonComparison to to modelsmodels

σ breakup consistent with values@SPS

CNM CNM effectseffects: : extrapolationextrapolation to to Cu+CuCu+Cu, , Au+AuAu+Au

Non suppression beyondCNM effects

Significant suppressionat forward-y

d+Au data set with much improved statistical precision is needed !

DataData drivendriven Extrapolation of CNM Extrapolation of CNM effectseffects to to Au+AuAu+Au

Larger range of CNM effects

than previous model

A d+Au data set with much improvedstatistical precision is needed !

J/J/ψψ in in Cu+CuCu+Cu ((nuclnucl--exex / 0801.0220v1)/ 0801.0220v1)

2.1 nb-1, 1.3 nb-1

<pT2> Independent of Npart for Cu+Cu

Agree with Au+Au

J/J/ψψ in in Cu+CuCu+Cu ((nuclnucl--exex/ 0801.0220v1)/ 0801.0220v1)

No-pt dependenceSimilar behaviour forward-midrapidity

Same behaviour Cu+Cu/Au+Au@ ~Npart

ProspectsProspects

c & b

Yan, Zhang, XuPRL 97 (2006) 232301

J/ψ

J/ψ flow : promising test of regenerationElliptic flow: collective phenomenon, transforms initial spatial anisotropy of collision region into momentum anisotropyElectrons from c and b quark meson decays have been observed with nonzero elliptic flow If regeneration takes place, J/ψ elliptic flow should show similar trend

Expected resolution of J/ψ v2 with 2007 data: QM2008 !?

BACKUP

Model competitionModel competition

•Orange solid : HSD, E.L.Bratkovskaya et al., PRC 71, 044901 (2005).•Blue : co-mover, A.Capella and E.G.Ferreirohep-ph/0610313.•Orange dashed : SCM, A.Andronic et al., nucl-th/0701079.

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

Au+Au mid rapidity data

• None reproduce RHIC data both at mid and forward rapidity well.• Relatively large errors in data at RHIC.• Relatively large variations in model predictions for RHIC.

Data and models at SPSPhys. Rev. C 69, 054903 (2004).

Good agreement!

J/J/ψψ ProductionProductionp+p Collisions

• Production Mechanism:cc pairs predominantly generated in hadronic collisions via gluonic diagramsDetails of hadronization process remain unclear

p

pJ/ψ

hard g

cc

p

pJ/ψ

soft g

cc

Color Singlet Model Color Octet Model pQCD with 3-gluons

X X ?Khoze et al Eur.Phys.J. C39 (2005)

PHENIX J/ψ Nuclear Dependence200 GeV dAu collisions – PRL 96, 012304 (2006)

somethingmore,dE/dx?

&more?

= X1 – X2

19 GeV

39 GeV

200 GeVopen charm: no A-depat mid-rapidity

J/ψ for different √s collisions

Data favors weak shadowing & absorption• With limited statistics difficult to disentangle nuclear effects• Need another dAu run!

Klein,Vogt, PRL 91:142301,2003

Low x2 ~ 0.003(shadowing region)

ασσ ANA =

Not universal vs x2 as expected for shadowing, but does scale with xF, why?• initial-state gluon energy loss?• Sudakov suppression (energy conservation)?

(x2 is x in the nucleus)

Cold Nuclear MatterTransverse Momentum Broadening

High x2~ 0.09

Low x2~ 0.003

PRL 96, 012304 (2006)ασσ ANA =

ccψ/J

gluonPHENIX 200 GeV results show pTbroadening comparable to that at lower energy (√s=39 GeV in E866/NuSea)Initial-state gluon multiple scattering

causes pT broadening (or Cronin effect)

J/J/ψψ kinematical distributionskinematical distributions• Study of differential distributions important in order to assess

• Role of initial state effects → pT distributions• Production mechanisms and/or deconfinement → polarization

• Technique• 3-D acceptance correction (pT, y, cosθ)• Fine binning (0.1 GeV/c pT, 0.05 y-units, 0.1 cosθ-units)• Define fiducial region (zone with local acceptance >1%)

-0.1<cosθH<0

pproj

ptargz

θCS

µ+y

x

Viewed from J/ψ rest frame

y

z

x θH

µ+

pproj ptarg

J/ψ

CollinsSoper

Frames forpolarization

studies

Helicity

J/J/ψψ polarization polarization • Quarkonium polarization → test of production models

• CSM: transverse polarization• CEM: no polarization• NRQCD: transverse polarization at high pT

αCS = -0.03 ± 0.17χ2/ndf =1.42

0 < pT < 5 GeV0.4 < yCM < 0.75

αH = 0.03 ± 0.06

χ2/ndf =1.01

0.5 < pT < 5 GeV0.1 < yCM < 0.6

• Deconfinement should lead to a higher degree of polarization(Ioffe,Kharzeev PRC 68(2003) 094013)

Polarization vs pPolarization vs pTT, y, centrality, y, centrality

0.1<yCM<0.80.5<pT<50.1<yCM<0.60.2<pT<5

• Helicity reference system (good coverage in NA60, -0.8<cosθH<0.8)

• No significant polarization effects as a function of• Centrality• Kinematical region

• Similar results in the Collins-Soper reference frame,albeit with much narrower coverage (-0.4<cosθCS<0.4)

Comparison with recent results (HERAComparison with recent results (HERA--B, E866)B, E866)

Helicity Helicity CollinsSoper

• HERA-B, in p-A collisions at 920 GeV, sees (mostly in the Collins-Soper reference system) a significant longitudinal polarization at low pT (P. Faccioli et al., Hard Probes 2006)

• No polarization in NA60, which covers a higher xF region

• E866, at still larger xF, sees a (slight) transverse polarization(T.H. Chang et al., PRL 91(2003), 211801)

SummarySummaryp+p data:

Provide a challenge for production modelspT spectrum mapped from 0-9 GeV/cRatio of forward and mid-rapidity pT distributions show a softening at forward rapidityRapidity distribution slightly flatter than most models and falls off more rapidly at forward rapidity

Au+Au data:Significant J/Ψ suppression in central collisions RAA~0.3Similarity between suppression observed at the SPS and RHIC is strikingSuppression weaker than pure color screening predictions

Recombination of uncorrelated quarks?Sequential dissociation of charmonium states?Other explanations??

NA60NA60--Conclusions and perspectivesConclusions and perspectives• NA60 has performed a high-quality study of J/ψ production

in Indium-Indium collisions at the SPS

• Confirms, for a much lighter system, the anomalous suppression seen in Pb-Pb collisions by NA50

• Onset of anomalous suppression at εBj ~ 1.5 GeV/fm3

• Preliminary results from p-A collisions at 158 GeV show thatthe normalization of the absorption curve is correct

• Peripheral In-In and Pb-Pb results are compatible with p-A

• Absence of J/ψ polarization in the kinematical window probed by NA60

• pT distributions sensitive to initial state effects

• Study of J/ψ suppression for other collision systems, with the accuracy allowed by a vertex spectrometer, would be very interesting

Comparison with extrapolations from Comparison with extrapolations from d+Aud+Au

Two calculations shownCNM effects model based on 1-3mb absorption and shadowing. (*)Glauber model + rapidity symmetrization of d+Au points (**)

RAA(±y) = RdA(-y)xRdA(+y)Suppression much higher than accountable by CNM effectsNot possible with Cu+Cu

No d+Cu/p+Cu run

Bar :

sta

t. +

unco

rrela

ted

syst

. erro

rsBo

x : c

orre

late

d sy

st. e

rrors

Err. Glo. = 12%

Err. Glo. = 7%

(*) R. Vogt, Acta Phys. Hung. A25 (2006) 97-103(**) R. Granier de Cassagnac, hep-ph/0701222

Testing sequential meltingTesting sequential melting

τ0 = 1 fm/cused here

SPS overall syst ~10%

PHENIX overall syst~12% & ~7%

KKS(*)

Latest L-QCD results suggest :No J/ψ suppression for T<1.5Tc ( ≳ 10GeV/fm3) complete only T>2.5Tc

ψ’and χc start melting at 1.1Tc (possibly at RHIC)Is suppression seen at RHIC & SPS only on feed down part?

Survival probabilityRAA/CNM

RHIC : σCNMabs = 1mbSPS : σCNMabs = 4.18mb

Cautionsτ0= 1fm/c too much for RHIC?CNM contribution at RHIC energy badly constrained!

(*) Karsch, Kharzeev, Satz, PLB 637 (2006) 75

Model resultsModel results

Reproduce experimental SJ/ψtot(=RAA/CNM).

Min. χ2 at (TJ/ψ, Tχ, fFD) = (2.02Tc, 1.22Tc, 30%)

2

_

2

)()()(

∑ ⎟⎟⎠

⎞⎜⎜⎝

⎛ −=

partN partdatastat

parttheorypartdata

NNSNS

σχ

Bar: uncorrelated sys.Bracket: correlated sys.

Onset of J/ψ suppressionat Npart ~ 160.( Highest T at Npart~160reaches to 2.02Tc.)

Gradual decrease of SJ/ψtot

above Npart~160 reflects that the transverse areawith T>TJ/ψ increases.

8International Nuclear Physics Conference 2007@Tokyo, Japan, T. Gunji

Sensitivity for TSensitivity for TJ/J/ψψ

TJ/ψ/Tc = 1.9, 1.96, 2.02, 2.08, 2.14Tχ = 1.22Tc and fFD=30%

TJ/ψ = 2.14TcTJ/ψ = 2.08TcTJ/ψ = 2.02TcTJ/ψ = 1.96TcTJ/ψ = 1.90Tc

Theoretical SJ/ψtot

is very sensitive to TJ/ψ.

International Nuclear Physics Conference 2007@Tokyo, Japan, T. Gunji 9

J/J/ψψ ProductionProductionAu+Au Collisions

• J/ψ Suppression Models:

– Assume quarkonia are formed only during the initial hard collisions– Subsequent interactions only result in additional loss of yield– Suppression of J/ψ yield with increasing collision centrality

Color Screening

ccrD

J/J/ψψ ProductionProductionAu+Au Collisions

• J/ψ Suppression Models:• J/ψ Recombination Models:

– In central heavy ion collisions more than one c-cbar pair is formed– Regeneration of J/ψ pairs from independently produced c and cbars– Increased J/ψ yield with increasing collision centrality– Narrowed J/ψ rapidity and pT distributions with increasing centrality

c

c c

c

cc c

c

cc

cc

J/J/ψψ ProductionProductionAu+Au Collisions

• J/ψ Suppression Models:• J/ψ Recombination Models:• Sequential Melting:

– J/ψ yield is populated from both direct production and feeddown from the higher resonance states

– Relative yield from each source experimentally found:60% direct production, 30% χc feeddown, 10% ψ’ feeddown

– Medium conditions determine whether each state is bound– Recent lattice results => J/ψ suppression turns on at T > 2 Tc

T < TC T ~ TC T ~ 1.1 TC T >> TC

Satz, J.Phys. G32 (2006) R25.

Screening in deconfined mediumScreening in deconfined medium

F. Karsch et al. (Nucl. Phys. A698(2002) 199c; hep-lat/0106019)

Color Screening

cc

Binding distance depends on quarkonium state“Melting” in QGP occurs at different temperatures

Debye screeningQCD screening lengthλD in deconfined medium decreases with temperatureQuarkonia “melt” when their binding distance becomes bigger than screening length

J/J/ψψ yield vs nuclear absorption (analysis b)yield vs nuclear absorption (analysis b)• Compare data to the expected J/ψ centrality distribution, calculated assuming nuclear absorption (with σabs =4.18 mb) as the only suppression source

require the ratio measured/expected, integrated over centrality, to be equal to the same quantity from the (J/ψ)/DY analysis (0.87 ± 0.05)

Nuclearabsorption

( )( )

( )( ) extrpA

centr all DYJ/ψµµ

meas centr all DYJ/ψµµ

ZDCZDCnucl.abs.J/ψ

ZDCZDCmeasJ/ψ

σσB

σσB

dE dEdN

dE dEdN=

∫∫

Normalization of thenuclear absorption curve

Smooth effect or sharp drop ?Smooth effect or sharp drop ?

Npart

Mea

s/E

xp

1

Step position

A1A2

Step position: Npart = 86 ± 8( εBj ~ 1.6 GeV/fm3 )A1= 0.98 ± 0.02A2= 0.84 ± 0.01χ2/dof = 0.7

• Taking into account the EZDC resolutiondata are compatible with a sharp drop

• An onset smoother than our resolution on Npart (~20) is disfavored• Work in progress to extend our Npart range towards more peripheral events

Models of J/Models of J/ψψ production production

J/ψ transport (Zhu et al, PLB 607 (2005) 107)

start with primordial charmonium from cold nuclear matter effect. Embedded in a relativistic hydrodynamics fireballCharmonoium suppressed by thermal gluon dissociation in the QGP.

Statistical hadronization (Andronic et al, PLB 571 (2003) 306)

Charm from primary collisions only. All charmonium destroyed in the QGP. Open and closed charm hadrons form

statistically at the chemical freeze-out.

Models of J/Models of J/ψψ production production

2 component model (Grandchamp et al, NPA 709 (2002) 415)Uses in-medium binding energies of charm states inferred from lattice.

Primordinal charmonium suppressed by partonic dissociation in QGP. Charm quark thermal relaxation time fitted to data. Additional charmonium from statistical hadronization of QGP. Suppression of all charmonium by hadroncollisions in HG phase. (continuous formation in QGP and HG)

Kenetic formation (Thews, hep-ph/0605322)Start with primordial charm distributions from cold nuclear matter effects. Allow continuous formation/destruction of J/ψ in QGP. Calculation done for no charm thermalization, full charm thermalization. Explored consequences of in-medium formation of pT, y distribution.

Models of J/Models of J/ψψ production production

Kinetic theory (Grandchamp et al, PRL 92 (2004) 212301)(Evolved from 2 component model)Uses in-medium binding energies of charm states inferred from lattice.

Primordial charmonium suppressed by partonic dissociation in QGP. Charm quark thermal relaxzation time fitted to data. Charmonium created/destroyed in QGP(HG) by ψ+X1 X2+c+c

Sequential melting (Karsch et al, PLB 637 (2006) 75)Start with primordial charm distributions from cold nuclear matter effects. J/ψ bound at RHIC. ψ’ and cc do not form in QGP. No destruction or formation of J/y after primordial formation. No interaction of J/ψ with the medium at all.

PHENIX J/PHENIX J/ψψ measurements summarymeasurements summaryJ/ψ counts J/ψ counts(|y|<0.35) (1.2<|y|<2.5)

1 Au+Au 130 1µb-12 Au+Au 200 24µb-1 13

p+p 200 0.15pb-1 46 65 PRC69, 014901(2004)3 d+Au 200 2.74nb-1 364 1186 PRL92, 051802(2004)

p+p 200 0.35pb-1 130 448 PRL96, 012304 (2006)4 Au+Au 200 241µb-1 1000 4449 nucl-ex/0611020

Au+Au 63 9µb-1

p+p 200 350nb-1

5 Cu+Cu 200 3nb-1 2300 9000 (prel.)nucl-ex/0510051Cu+Cu 62 0.19µb-1 146Cu+Cu 22.5 2.7µb-1

p+p 200 3.8pb-1 1500 8005 hep-ex/06110206 p+p 200 10.7pb-1

p+p 62 0.1pb-1

7 Au+Au 200 4x run 4?

ReferenceRun Species √sNN[GeV] ∫Ldt

Running