Status and Future Perspective of J/  Measurement in Heavy Ion Collisions T. Gunji Center for Nuclear Study University of Tokyo Heavy Ion Café: 2008/6/28 T. GunjiTitle1/42

Introduction Physics Motivation Charmonium and the Medium Results from SPS and RHIC Future Perspective Summary Heavy Ion Café: 2008/6/28 T. GunjiOutline2

Bound system between ccbar. m c ~1.3 GeV Heavy and small system. Long lived (compared to LVM [ , ,  ] ) Can be measured via di-lepton decay. Heavy Ion Café: 2008/6/28 T. GunjiIntroduction3 J/  family (J/ ,  ’,  c ) T. Gunji, D-thesis

Heavy Ion Café: 2008/6/28 T. GunjiIntroduction4 Feed down from excited states J/  = direct J/  + feed down from  ’ and  c 20% ~ 40% from  c ~ 10% from  ’ S. X. Oda QM2008

Heavy Ion Café: 2008/6/28 T. GunjiPhysics Motivation5 Color Screening When Quark-Gluon-Plasma is formed, the attraction between ccbar pairs is reduced due to the color screening. T. Matsui and H. Satz (1986) This leads to the suppression of quarkonia yield. Suppression depends on temperature of the medium and radius of qqbar system. T. Matsui and H. Satz PLB 178, 416, (1986)  ccbar ~ 0.06fm, exp(-2m c /T c )~10 -7

Heavy Ion Café: 2008/6/28 T. GunjiPhysics Motivation6 Melting Temperatures cc J/  cc S. Digal, F. Karsch and H. Satz T/T C 1/  r  [fm -1 ]  (1S) J/  (1S)  c (1P)  ’(2S)  b ’(2P)  ’’(3S) A.Mocsy HP2008 Potential Model & lattice simulations T c ~270 MeV J/  may survive up to 2T c, while  c and  ’ are melt at 1.1T c. Asakawa & Hatsuda, hep-lat/ Aarts et al., hep-lat/ T. Hatsuda QM2006 (hep-ph/ ) Datta, Karsch, Petreczky & Wetzorke, hep-lat/ Other results:  c may survive up to ~2T c. [T. Umeda, PRD. 75, (07)] J/  may be dissolved at ~1.2T c. [A. Mocsy et al, PRL 99(2007)211602, HP’08]

Heavy Ion Café: 2008/6/28 T. GunjiPhysics Motivation7 pT dependence of Screening Leakage effect high pT J/  can escape the medium. depends on formation time. (medium vs. J/  ) Hot-wind scenario Melting temperature depends on relative velocity between J/  and medium. M.C.Chu and T. Matsui PRD 37 (1998) 1851 H. Liu et al. hep-ph/

Heavy Ion Collisions  Study of QGP J/  measurement in heavy ion collisions has been performed at SPS and RHIC. Heavy Ion Café: 2008/6/28 T. GunjiPhysics Motivation8 Experiment at SPS and RHIC LEP/LHC SPS PHENIX NA38/NA50/NA51/NA60 √s NN ~ GeV S+U, p+p, p+d, p+Pb, Pb+PB, In+In ……. PHENIX/STAR √s NN = 200 GeV (x10 SPS) p+p, d+Au, Cu+Cu, Au+Au STAR

All stage of collisions modify the J/  yield. Heavy Ion Café: 2008/6/28 T. GunjiCharmonium and the Medium9 Fate of J/  in Heavy Ion Collisions Hot and dense medium Nuclear medium Gluon Shadowing CGC Nuclear Absorption Cronin Color screening Gluon dissociation Recombination Comover DDbar  J/  +h Initial stage Hadronic Matter

Gluon Shadowing Depletion of Gluon PDF in nuclei Color Glass Condensate Gluon saturation from non-linear gluon interactions for the high density at small x Larger effect for heavier nuclei Heavy Ion Café: 2008/6/28 T. GunjiCharmonium and the Medium10 Initial State Effects Eskola et al. NPA696 (2001) 729 gluons in Pb / gluons in p x Anti Shadowing SPS : x~0.1 RHIC: x~10 -2 LHC: x~3x10 -4

Nuclear Absorption Dissociation of J/  or pre-resonance by spectators. Cronin effect Multiple scattering of partons Heavy Ion Café: 2008/6/28 T. GunjiCharmonium and the Medium11 Cold Matter Effects J/ψ L σ abs = 4.18 ± 0.35 mb at SPS

Recombination of J/  from uncorrelated ccbar pairs P = N ccbar /N h, N J/  = N ccbar 2 /N h N ccbar (N h ) scales with N col (N part ). N ccbar grows faster with CMS energy Negligible at SPS. But not at RHIC. Huge at LHC. Charm production needs to be understood. Two models: Statistical hadronization (A. Andronic et al.) Formation at phase boundary according to statistical law. Kinetic formation (R. Rapp et al.) In-medium formation and destruction by thermal gluons. Heavy Ion Café: 2008/6/28 T. GunjiCharmonium and the Medium12 Recombination

Medium effects on J/  suppression Color screening : collective effect ccbar is not bound to form J/  Dissociation of J/  by (thermal) gluons If J/  is formed, energetic gluons (comoving hadrons) could dissociate J/ . J/  + g  ccbar (+g) Both depends on: formation time of QGP and J/  (  8 ~0.3fm) field map of T and  and its space-time evolution Screening : melting temperature and decay width Dissociation: cross section (decay width) Heavy Ion Café: 2008/6/28 T. GunjiCharmonium and the Medium13 Screening and Gluon Dissociation They are crucial and to be understood in detail to study the J/  suppression and compare to the experimental data.

How it behaves around T diss ? Screening: Lattice knows? Dissociation: Rely on pQCD? Cross section of J/  +g->cc(g) Reliable in QGP? Reliable for higher states? Heavy Ion Café: 2008/6/28 T. GunjiCharmonium and the Medium14 Decay width G. Bhanot NPB 156 (1979) 3916 k[GeV]  J/  +g ¼   +g Gluon dist. (T=0.35 GeV) X.N.Wang PLB540 (2002) 62 Decay width (cross section with gluons) in QGP is most important quantity to study J/  suppression (even for recombination) How much it is understood in detail? R. Rapp et al hep-ph/ ? TdTd 

Cold Matter effects GeV (NA50) GeV (NA60) Heavy Ion Café: 2008/6/28 T. GunjiResults from SPS and RHIC15 Results from SPS Stronger suppression than the cold matter N part >150. Very preliminary P. Cortese HP2008

Suppression at low pT (<2-3 GeV) Cronin effect Leakage effect. No hot-wind effect(?) Heavy Ion Café: 2008/6/28 T. GunjiResults from SPS and RHIC16 pT dependence of Suppression R. Arnaldi QM2008 L. Ramello QM2005

Dissociation by thermal gluons Heavy Ion Café: 2008/6/28 T. GunjiResults from SPS and RHIC17 J/  suppression at SPS (1/2) 158 GeV E T [GeV] R. Rapp PLB92 ( 2004 ) X.N.Wang PLB540 (2002) 62 NA60 In-In 158 GeV preliminary J/  +g  ccbar (pQCD) J/  +g  ccbar +g

Sequential Suppression (screening) Only  ’ and  c melt. (~40%) S (J/  ) = 0.4*S(  c,  ’)+0.6 Well agreement with data Heavy Ion Café: 2008/6/28 T. GunjiResults from SPS and RHIC18 J/  suppression at SPS (2/2) J/  ’’ F. Karsch et al., PLB, 637 (2006) 75

NA50/NA60 (Pb+Pb, In+In) Large v2 Difficult to understand N cc is low (no recombination) No charm thermalization Due to anisotropic absorption in QGP/nuclear matter? Heavy Ion Café: 2008/6/28 T. GunjiResults from SPS and RHIC19 v2 of J/  at SPS NA50 NA60 v2v2 X.N.Wang PLB540 (2002) 62 HP2008 R. Arnaldi QM2008

Heavy Ion Café: 2008/6/28 T. GunjiResults from SPS and RHIC20 R AA vs. N part at RHIC |y|< <|y|<2.2 R AA (1.2<|y|<2.2) < R AA (|y|<0.35) ~ R AA at SPS (0<y<1) Why? PRL.98, (2007) arXiv:

Suppression is low pT J/  (<5GeV). Heavy Ion Café: 2008/6/28 T. GunjiResults from SPS and RHIC21 pT dependence of RAA PRL.98, (2007) QM2008

d+Au collisions Heavy Ion Café: 2008/6/28 T. GunjiResults from SPS and RHIC22 Cold Matter Effect in d+Au at RHIC Breakup cross section PRC (2008) F. Fleuret HP2008 Break up cross section is compatible to SPS. Need more statistics to constraint cold matter effects.

Extrapolate Cold Matter effect to Au+Au. Heavy Ion Café: 2008/6/28 T. GunjiResults from SPS and RHIC23 R AA vs. Cold Matter effect EKS shadowing model arXiv: J/  suppression starts at: N part ~200 at mid-rapidity N part ~100 at forward rapidity R AA (1.2<|y|<2.2) < R AA (|y|<0.35) R AA (RHIC |y|<0.35) ~ R AA (SPS) 1: Dissociation + Recombination dissociation should be similar but recombination is larger at mid-y. 2: Initial state effect (CGC) Suppression of J/  production at forward-y due to CGC effect. 1: Stronger dissociation at RHIC supplemented by Recombination 2: Sequential melting and Melting J/  at higher temperature

A. Andronic et al. assuming: No survival J/  above N part >80 Heavy Ion Café: 2008/6/28 T. GunjiResults from SPS and RHIC24 Statistical Hadronization NPA 789 (2007) 334, PLB 652 (2007) 259, PLB 659 (2008) 149 I 1 /I 0 cc inputoutput Input charm y distribution d  /dy=63  b d  /dy=123  b (PHENIX)

R. Rapp et al. L. Yan et al.….. Heavy Ion Café: 2008/6/28 T. GunjiResults from SPS and RHIC25 Kinetic formation R. Rapp et al. L. Yan et al. R AA N part J/  +g  c+c arXiv: PRL 97 (2006) How we precisely know decay width of J/  in QGP?

A. Capella et al. SPS: Comover alone with  co = 0.65mb Good for Pb+Pb but Failed for In+In RHIC: inclusion recombination Heavy Ion Café: 2008/6/28 T. GunjiResults from SPS and RHIC26 Comover + Recombination Number of binary col. Multiplicity in p+p Non-diffractive p+p cross section Tywoniuk QM08, arXiv:

Saturation could suppress forward J/  in Au+Au First numerical estimate, work in progress M. Nardi, D. Kharzeev, E. Levin, K. QM2008 Heavy Ion Café: 2008/6/28 T. GunjiResults from SPS and RHIC27 Effect of Color Glass Condensate Calculations based on CGC can reproduce y and b dependence of J/  in Au-Au at RHIC. Some uncertainty in absolute normalization, leaving room for final state suppression.

Hydro + J/  Model Heavy Ion Café: 2008/6/28 T. GunjiResults from SPS and RHIC28 Sequential Melting at RHIC T. Gunji et al. Phys. Rev. C 76: (R), 2007 First attempt for the study of sequential suppression of charmonia at RHIC. –Incorporate J/ ,  c and  ’ into the evolution of matter. Evolution of matter : (3+1)-dimentional relativistic hydrodynamics –T. Hirano and Y. Nara, PRL 91, , (2003) –T. Hirano and Y. Nara, PRC 69, , (2003) –T. Hirano and K. Tsuda, PRC 66, , (2002) – tokyo.ac.jp/~hirano/parevo/parevo.html J/ ,  c and  ’ : impurity traversing through the matter –Assume three kinds of interaction inside QGP. »Free Streaming »Hot-Wind »Complete Thermalization

Survival Prob. In the medium: Decay Width: Motion of J/  : free streaming Total Survival Prob. Free Parameters: (T J/ , T , f FD ) J/  x0x0   (p T ) x 0 (Production point) is distributed according to the spatial N col distribution. p T is distributed according to the measured J/  distribution. J/  azimuthal angle, , is flat (0 to 2  ). Heavy Ion Café: 2008/6/28 T. GunjiResults from SPS and RHIC29 Modeling of J/  suppression

Compare survival probability in the medium. Heavy Ion Café: 2008/6/28 T. GunjiResults from SPS and RHIC30 Results Onset of J/  suppression at N part ~ 160. Gradual decrease of S J/  tot above N part ~160 reflects that the transverse area with T>T J/   increases. Very sensitive to T J/  and T J/  is consistent with lattice results. Best (T J/ , T , f FD ) = (2.00Tc, 1.34Tc, 10%)

Heavy Ion Café: 2008/6/28 T. GunjiResults from SPS and RHIC Decay width below T melt T. Song, Y. Park and S. H. Lee Phys.Lett.B659: ,2008. Decay width below T J/y is very small.  <

Heavy Ion Café: 2008/6/28 T. GunjiResults from SPS and RHIC32 Other observables  S AA vs. pT v2 vs. pT  Free streaming Hot-wind Suppression is flat in case of free streaming and stronger for high pT J/  in case of hot-wind. v2 is small (<1%) in case of free Streaming and larger for higher pT in case of hot-wind (~3% v2). 3% 20-30%0-10%20-30%0-10% 40-50%50-60% 20-30% 0-10% 40-50%

Heavy Ion Café: 2008/6/28 T. GunjiResults from SPS and RHIC33 J/  v2 at RHIC NA50 D. Krieg et al. arXiv: Need more data!! Challenging to understand both SPS and RHIC data. Negative v2 is possible, when J/  is formed via recombination like light hadrons and charm quarks locally equilibrated. Just Mass Ordering!!

Now. Need to study: Decay width of quarkonia states in QGP (vs. T) Charm production and recombination Initial state effect such as CGC.  ’,  c,  states, v2, pT dist. … High statistics data from RHIC (d+A, A+A)!! Go to higher energy (temperature). LHC!! Heavy Ion Café: 2008/6/28 T. Gunji34 Where we are now? Where we go? Results from SPS and RHIC CGC Dissociation +Recombination sequential suppression (J/  melt at RHIC) dissociation + recombination (same amount btw. mid and forward) Decay width? charm production? No Yes

Heavy Ion Café: 2008/6/28 T. GunjiFuture Perspective35 RHIC Run8 d+Au collisions 57,030 J/    (~73,000 from all data) 4,369 J/   ee (~6,000 from all data) 59 nb nb -1 ~30 times larger stat. compared to run3 Expected improvement in constraints of cold matter effect (red) compared to Run3 (blue) expected accuracy simulation

PHENIX upgrade NCC, forward VTX (J/  /  ’,  c at forward) STAR upgrade Forward muon, full EMC+TOF, HFT Luminosity Heavy Ion Café: 2008/6/28 T. GunjiFuture Perspective36 RHIC future max min #  x100 #J/  100,000 J/    and ~250    per year at highest RHIC luminosities J/  &    M. Leitch WWND2008

Starts its operation from this summer!! Heavy Ion Café: 2008/6/28 T. GunjiFuture Perspective37 Large Hadron Collider at CERN 3-42> 1T / T c 2x10 4 7x V f (fm 3 )  (GeV/fm 3 ) 1-3  dN ch /dy  s (GeV) LHCRHICSPS Central collisions  2  p+p,  s = 0.9/10 TeV 2009 p+p,  s = 14 TeV, cm -2 s -1 Pb+Pb,  s NN = 5.5 TeV, 5×10 25 cm -2 s ~ p+p,  s = 14 TeV, cm -2 s -1,  s = 5.5 TeV, cm -2 s -1 Pb+Pb,  s NN = 5.5 TeV, cm -2 s -1 p+Pb,  s NN = 8.8 TeV, cm -2 s -1 Ar+Ar,  s NN = 6.3 TeV, cm -2 s -1 K. Shigaki JPS2008 LHC: ~ 30x larger in √s NN w.r.t. RHIC T ~ x RHIC  ~ 3-6 x RHIC ALICE LHC-b ATLAS CMS

Heavy Ion Café: 2008/6/28 T. GunjiFuture Perspective38 Impact on Quarkonia measurement SPS RHIC LHC 30 complete suppression enhanced recombination Large production cross section x100 RHIC for bottom x10 RHIC for charm Cleary see J/  enhancement or strong suppression Bottomonia suppression  would melt only at LHC  ’ T d ~ J/  T d Small  regeneration  ’ can unravel J/  suppression vs. regeneration Much smaller x than at RHIC down to x~10 -4 with charm at y=0 CGC, PDF … X 1,2 = M/√s e  y K. Itakura QM05

Heavy Ion Café: 2008/6/28 T. GunjiFuture Perspective39 ALICE J/ , ϒ  ee at mid-rapidity |  |<0.9 ITS+TPC: p TPC+TRD: eID J/ , ϒ   at forward-rapidity -4  2.5 CNS, Tsukuba: TRD Hiroshima: PHOS

Wide y and pT coverage ALICE: J/  and ϒ ATLAS and CMS : ϒ Heavy Ion Café: 2008/6/28 T. GunjiFuture Perspective40 Acceptance

ALICE Physics Performance Report Vol. 2: J. Phys. G (2006) Heavy Ion Café: 2008/6/28 T. GunjiFuture Perspective41 Physics Performance Di-electron Mass dist. in Pb+Pb (one year) nPDF+shadowing+HIJING( ~3000) Separations of J/ ,  ’ and ϒ,ϒ’, and ϒ’’. Di-muon Mass dist. in Pb+Pb (central) centralS[10 3 ]B[10 3 ]S/B S/  (S+B) J/  ’’  (1S)  (2S)  (3S)

J/  suppression characterizes the properties of QGP. But Production of J/  in heavy ion collisions is complicated. initial ~ cold matter ~ screening, dissociation, recombination… Feed down from higher states SPS: sequential melting or gluon dissociation. Conclusion depends on the decay width (step-like vs. pQCD base) prevents the firm conclusion (even at RHIC!!). RHIC: “SPS + CGC” or “SPS + Recombination (mid-y)” Charm production is key for recombination. (especially y dist.) Need to do and future… precise calculation of the decay width in “QGP” (vs. T). study of initial state effect high statistics (charm production, CGC, cold matter, v2, pT dist.) simultaneous study at “RHIC+LHC”. LHC!! Heavy Ion Café: 2008/6/28 T. GunjiSummary42 Summary

Backup slides

Production of ccbar pairs m c ~1.3 GeV  s (m c )«1. Pertubavative.  1/2m c. Process takes place in short time. Hadronization Color Singlet Model (pQCD) Color Evaporation Model Color Octet Model (NRQCD)  8 ~ 1/sqrt(2m c  QCD )=0.25fm Still working hard: pT distribution, polarization (CDF, RHIC). feed down, J/  -h correlation (RHIC) Heavy Ion Café: 2008/6/28 T. GunjiIntroduction5 Production (in vacuum) H. D. Sato

Heavy Ion Café: 2008/6/28 T. GunjiResults from SPS and RHIC4 pT dist. of J/  Statistical hadronization A. Andronic et al. nucl-th/ , Nucl.Phys.A789: ,2007