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V. Greco Università di Catania, Italy INFN-LNS

Quark-Gluon Plasma Dynamics in ultra-Relativistic Heavy-Ion Collisions-II. V. Greco Università di Catania, Italy INFN-LNS. Scuola Di Fisica Nucleare “Raimondo Anni” (IV corso) Otranto, 1-5 giugno 2009. Hadronization and Open Heavy Flavor. Hadronization Modified

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V. Greco Università di Catania, Italy INFN-LNS

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  1. Quark-Gluon Plasma Dynamics in ultra-Relativistic Heavy-Ion Collisions-II V. Greco Università di Catania, Italy INFN-LNS Scuola Di Fisica Nucleare “Raimondo Anni” (IV corso) Otranto, 1-5 giugno 2009

  2. Hadronization and Open Heavy Flavor • Hadronization Modified • RAA-RCP-V2 for baryon and mesons • Basic Theory of coalescence(phase –space) • coal. vs fragm. - application to RHIC • RAA – v2 and B/M in the coalescence mechanism Outline • Heavy Quark interaction in the plasma • problematic relation between RAA and v2 • presence of heavy-light Qq resonances (lQCD) • relevance of Hadronization mechanism

  3. Surprises… Baryon/Mesons Quenching Au+Au p+p PHENIX, PRL89(2003) p0 suppression: evidence of jet quenching before fragmentation In vacuum p/p ~ 0.3 due to Jet fragmentation Protons not suppressed • Jet quenching should affect both Hadronization has been modified pT < 4-6GeV !?

  4. Leading Particle Effect Reservoir of partons modifies hadronization Quark-Antiquark Recombination in the Fragmentation Region • K.P. Das & R.C. Hwa: Phys. Lett. B68, 459 (1977): • Braaten, Jia, Mehen: Phys. Rev. Lett. 89, 122002 (2002) • Rapp and Shuryak, Phys. Rev. D67, 074036 (2003) beam E791 - beam: - hard cc production; - c recombine with d valence from - -> D- enhancement =0 from LO fragmentation Similarly for p+/p-, K+/K- at ISR/Fermilab (late ‘70) In HIC the resorvoir is the thermal bulk!

  5. Hadronization in Heavy-Ion Collisions H Partonspectrum • Initial state: no partons in the vacuum but a thermal ensemble of partons • No direct QCD factorization scale for the bulk: dynamics much less violent (t ~ 4 fm/c) • dense parton systems no need for creation and splitting Fragmentation: • energy needed to create quarks from vacuum • hadrons from higher pT Baryon Coal. Coalescence: Meson • partons are already there $ to be close in phase space $ • ph= n pT ,, n = 2,3 baryons from lower momenta (denser) Fragmentation ReCo pushes out soft physics by factors x2 and x3 ! V. Greco et al./ R.J. Fries et al., PRL 90(2003)

  6. Basic Theory Discard details of dynamics -> adiabatic approximation: instantaneous projection of initial state onto final cluster FM(r,q) Meson wave function fragmenting parton: ph = z p, z<1 Wab two parton distribution function Approximation in FMNB (Hwa-Yang) • - Go in the  momentum frame • - Neglect the transverse momentum • Neglect r,p correlations recombining partons: p1+p2=ph Fries, QM’04 All fairly good approximations At pT > 2 GeV/c xi light con momentum fraction CM spin-isospin color factor

  7. Specific features of Reco in HIC P-> ∞or m=0 • ReCo is very effective for thermal spectra: Parton Meson For baryons you will get the same as for mesons Opposite to the suppression from fragmentation • ReCo is very effective for power law spectra: Fragmentation Coalescence More effective than Reco So eventually Fragmentation takes over … Need of Coalescence + Fragmentation model

  8. Is coalescence ”too simple”? “The best physicist in the USSR is Yakov Frenkel, who uses in his papers only quadratic equations. I am slightly worse, I sometimes use differential equations.” L.D.Landau, quoted in BULLETIN OF THE American Mathematical Society 43, Number 4, October 2006, Pag. 563−565 R.J. Fries, V. Greco, P. Sorensen - Ann. Rev. Nucl. Part. Sci. 58, 177 (2008)

  9. Phase-Space Coalescence (GKL) 3D-geometry with radial flow space-momentum correlation gH statistical factor color-spin-isospin • fqinvariant parton distribution function • thermalwith radial flow(b=0.5r/R) • quenched minijets (GLV- L/l = 3.5) gg -> qq , suppressed by mass (g->qq no dire effects) npQCD also encoded in quark masses (gluon dressing), mq=0.3 GeV, ms=0.475 GeV. fHhadron Wigner function Dx = 1/Dp (real free parameter different) If <r2> is fixed results are nearly indipendent on the w.f. shape

  10. Parton bulk matter parameters T=170 MeV quenched ET ~ 740 GeV T ~ 170 MeV b(r)~ 0.5 r/R soft hard L/l=3.5 P. Levai et al., NPA698(02) e ~ 0.8 GeVfm-3 dS/dy ~ 4800 Parton distributions Experiments lQCD Tc like Hydro Bulk matter consistent with hydro, experiments, lQCD Hadron from coalescence may follow jet structure (away suppr.) REALITY: one spectrum with correlation kept also at pT < 2 GeV Coalescence at QCD phase transition

  11. FMNB Meson & Baryon Spectra Au+Au @200AGeV (central) sh GKL V. Greco et al., PRL90 (03)202302 PRC68(03) 034904 R. Fries et al., PRL90(03)202303 PRC68(03)44902 R. C. Hwa et al., PRC66(02)025205 • Proton suppression hidden by coalescence! ReCo dominates up to 4 (meson)-6(baryon) GeV/c; Fragmentation + energy loss takes over above.

  12. Baryon/Meson ratio TAMU r-> pp Strange particles from a common quark flow Hwa-Yang FMNB

  13. Yields for baryon and mesons were not the only surprise at RHIC

  14. Elliptic flow from Hydro • Mass-dependence of v2(pT) suggests common transverse velocity field large • At higher pT v2 for Baryon=Mesons in both - hydrodynamics - jet fragmentation • Again surprise Baryon ≠Mesons : v2 larger for Baryons

  15. Coalescence carries another features … Coalescence scaling Enhancement of v2 v2q fitted from v2p GKL Considering only momentum space x - p correlation neglected narrow wave function Molnar and Voloshin, PRL91 (2003) • v2 for baryon is larger and saturates at higher pT (more baryons in plane) baryons • Quark number scaling! Again agreement with unexpected observation mesons No free parameter !

  16. Better scaling vs KET/nq It is related with energy conservation

  17. PHENIX, PRL (07) • nq - not a mass effect • Most of flow is partonic Mass or quark number? F(1020) • Mass of the hadrons is not relevant • rules out explanations blaming collective motion • Confirmation v2 develops during partonic phase Confirmed also by K*(892) measurements

  18. RAA–RCP and v2 Correlation Coalescence reverts the correlation Between RAA & v2: both are enhanced This rules out other explanations: Baryon junctions, hydro+jets Rcp~1 with large v2 P.Sorensen This effect is essential also for the study of charm quark interaction

  19. Take home messages from the light sector • Hadronization from 2-3 body phase SPACE (pT< 5-6 GeV): • dense medium decrease vacuum role • massive quarks close in phase space • hadrons at pt comes from quarks pt/n (shift of soft scale) • Universal elliptic flow (dynamical quarks “visible”): • carried by quarks • enhanced by coalescence R.J. Fries, V. Greco, P. Sorensen - Ann. Rev. Part. Sci. 58, 177 (2008) Result are robust against Uncertainty in resonance, Wave function, higher Fock states. Energy conservation

  20. Ok, but this is really too naive… !? Less important at high pT Stability of Reco results respect uncertainties in their treatment high pT the problem suppressed by m/pT but even at low pT is not so drammatic • Resonances (included in GKL) • Wave function finite width • Gluons • ALCOR, GKL : mass suppressed, quark dressing, splitting • Fries-Muller-Bass, PLB618 (05): Higher Fock States • 4) Energy Conservation • not large 17% in GKL, resonances decay & v2 • Ravagli-Rapp PLB655(2007) for v2(KET) • 5) Entropy Conservation • 15% like energy – mass, resonances, expansion • 6) Relation to jet-like correlations • Consistent with ReCo-Fries et al., PRL94, but need of a transport description • 7) Space-momentum correlations affect v2 scaling • Pratt-Pal PRC71, Molnar nucl-th/0408044, Greco-Ko nucl-th/0505061, • Rapp-Ravagli arXiv:0806.2055

  21. LHC RHIC SPS Zhu et al. (2006) What happens to heavy quarks?

  22. Specific of Heavy Quarks Comparing mHQ to LQCD and T • mc,b >> LQCDproduced by pQCD processes (out of equil.) • t0~1/mc,b << tQGPthey go through all the QGP lifetime • mc,b >> T0no thermal production • teq >tQGP >> tq,gsensitive to interaction (even at low pT) • m >>T transport reduced to a Fokker-Planck • lQCD calculation of spectral function(quark loop damped) • Concept of potential V(r) <-> lQCD (also nrEFT) : QGP <-> lQCDstudy sQGP

  23. Heavy Quarks in the Quark Gluon Plasma -> Quarkonium suppression 2. Open Heavy Flavor D(cq) B(bq) because mq<<mc,b study their spectra means study the scattering of c,b in the medium -> Spectra: RAA, v2(pT) of open heavy flavor

  24. In the vacuum a potential model gives very good result H. Satz

  25. × k pi pf pi pf c k a Energy Loss for Heavy Quarks g c • Elastic Collisional energy loss - till now neglected in the light quark sector • Induced gluon emission - mass effect (“dead cone”) In perturbative plasma physics: gv=p/m >>1/g radiative (bremsstrahlung) is dominant At 2TC it means p>>1 GeV for charm • Scattering on resonant states - suggestion from lQCD (spectral function & potential model)

  26. What is measured till now is the single e the lepton can be reconstructed Single-Electron Decays D-Mesons • bottom crossing at 5GeV !? • strategy: fix charm with D-mesons, • adjust bottom in e±-spectra b/c similar to pQCD Cacciari, Nason, Vogt, PRL95(2005)

  27. RAA , v2 of single e – Jet Quenching q q S. Wicks et al., nucl-th/07010631(QM06) N. Armesto et al., PLB637(2006)362 • Radiative energy loss not sufficient • sQGP:non perturbative effect Main Challenge is the in-medium quark interaction lQCD resonant (bound) states persist for QQ and qq -> Qq (D-like) resonant scattering

  28. “Light”-Quark Resonances 1.4Tc [Asakawa+ Hatsuda ’03] Spectral function in lQCD A(w)=w2r (w) Asakawa J/Y Studied in Potential model for J/Y - Mannarelli, Rapp - PRC72 (Bruckner-like) - Alberico, Beraudo, De Pace, Molinari - PRD 72 & 75 J/y (p = 0) disappears between 1.62Tc and 1.70Tc

  29. Equilibration time pQCD QGP- RHIC “D” Open-Charm Resonances in QGP As first test we used an effective model: 2 parameters: GD , mD • effective model with pseudo/scalar • + axial/vector “D-like” mesons • [chiral + HQ symmetry] • cross section ISOTROPIC • t eqdown to 5 fm/c at RHIC ! Ok, but can it describe RAA and v2?

  30. The model HQ scattering in QGP Langevin simulation in Hydro bulk c,b quarks T<<mHQ sQGP • Elastic pQCD • LDcq • T-matrix V(r)-lQCD From scattering matrix Hadronization Coalescence + Fragmentation c,b Semileptonic decay RAA & v2 of “non-photonic” e (with b contamination ) K (D) D (B) e ne

  31. Prediction forv2andRAAwith resonance model coalescence + fragment. fq from p, K Greco,Ko,Levai - PRL90 Hees, Greco, Rapp - PRC73(06) QM’06 pQCD Reson. • Simple upscaling of pQCD scattering cannot get RAA-v2(Teaney) • coalescence increases both RAA and v2(anti-correlation) • It is worth to pursue the in-medium resonance idea!

  32. Are there really hadronic-like resonances? Diffusion coefficient from V(r) lQCD

  33. VlQCD gives resonance states! V(r) parametrizion by Wong, PRC72(2005) Scattering states included: Singlet + Octet –triplet -sextet “Im T” dominated by meson and diquark channel Kaczmarek et al., PPS 129,560(2004) Brueckner calculation • Solve in partial wave expansion • Equation closed with the equivalent equation in the light sector,here simplified with a constant m and G

  34. Drag and Diffusion from lQCD-V(r) Opposite T-dependence of g • RAA is built in the early stage • V2 in the later stage • With lQCD- V(r): • -> less RAA and more V2 • -> v2 generation delayed lQCD Friction coefficient pQCD ImT increase with temperature compensates for decreasing scatterer density

  35. T-matrix calculation vs revised PHENIX data • One can get both RAA and v2 • with no free tunable parameters: • Uncertainties: • in the parametrizationof V(r) • in the extraction of V(r) (U vs F) B suppression larger than the first expectation from LqbB Essential ALICE (LHC) that will disentangle the two contributions Hees-Mannarelli-Greco, PRL100 (2008)

  36. Impact of hadronization mechanism • Improved RAA - V2correlation • toward a better agreement with data • naturally merging into • a coalescence mechanism Impact of hadronization Hees-Mannarelli-Greco, PRL100 (2008)

  37. Successful model so be more careful: • Critical the choice between U=F-TS and F • Improve consistency between coalescence and fireball evolution • include radiative energy loss • disentangle B and D contribution for a safe comparison • (ALICE-LHC)

  38. From the point of view of the shear viscosity lQCD-quenched

  39. From RHIC to LHC? For min. bias. Hydro bulk dN/dy=1100 (dN/dy=2200 for central) Tinit= 3 Tc Radial flow bmax=0.68 V2q light quark =7.5 % (hydro or numerology) v2q(pT) from a cascade [ Ferini,Colonna, Di Toro,VG] dN/d2pT of b,c from PYTHIA (ALICE PPR-JPG32) Resonances off T>2Tc Borghini-Wiedemann,JPG3508) Calculation not done with lQCD, but

  40. From RHIC to LHC - RAA RHIC LHC bottom bottom charm charm • Suppression: RAA similar at RHIC and LHC! • Harder initial spectra at LHC • Resonance ineffective (“melted” T>2Tc) at early stage! • For 3-body scattering opposite behavior !

  41. From RHIC to LHC – v2 electrons RHIC LHC from D only ALICE • v2 similar at RHIC and LHC! • Resonance effective when anisotropy is reduced • Strong drag with the bulk flow at later stage! • v2 slightly higher at low pt • For 3-body scattering opposite behavior !

  42. Picking-up 3+1 results at RHIC Ideal Hydrodynamics works well: • good description of dN/dpT , v2(pT) • mass-ordering & v2(pT)/e scaling pT <2 GeV Perfect fluid • We have not just a bunch of particles, but a transient state of high energy plasma with • - Strong collective phenomenain conditions similar to those 10-5 s after the Big Bang • ~15 GeV/fm3 >> ec T~ 350 MeV h/s ~0.1 (lQCD) - Hadronization is modified and thereevidences of quark degrees of freedom - Very opaque to jets -sQGP Hadronization modified: • B/M ratio consistent with quark coalescence • v2(pT) scales with the number of quarks 2<pT <6 GeV Quarks degrees of freedom Jet-quenching (gluon-radiation) observed: • hadrons RAA <<1 and flat in pT • photons no quenching pT >6 GeV High opacity Heavy Quarks: • not expected small RAA and large v2 • RAA and v2 not accounted by jet quenching mT >1.5 GeV Hadronic-like resonances

  43. Picking-up four main results at RHIC • Viscous Hydrodynamics works well (pt<1.5 GeV): • good description of dN/dpT , v2(pT) • what’s the value of shear viscosity h/s ? Bulk viscosity? • Hadronization is modified (1.5<pt<6 GeV): • B/M anomalous ratio and v2(pT) quark number scaling • is the v2(pt) consistent with the h/s of sQGP? • Jet-quenching (gluon-radiation) observed (pt>6 GeV): • all hadrons RAA <<1 and flat in pT, suppression is jet-like • Mach-cone like correlation observed at pt<4 GeV • What is the nature of the double peak structure? Elastic contribution, time dependendence, flavor changing… • Heavy quarks strongly interacting: • small RAA large v2 (hard to get both) pQCD fails • presence of hadronic-like resonances + need of coalescence • need of lQCD spectral function, measurement of D and B separately

  44. What we have found and what we expect at LHC! • Develop a transport to control viscosities effect, study the jet-bulk cone, chiral mass generation • lQCD spectral function with widths for heavy hadrons • Microscopic structure of sQGP (for HQ it’s closer) • Determine shear viscosity and its temperature dependence (->LHC • J/Y suppression-regeneration is not clear (->LHC • Mechanism of jet quenching is not clear (->LHC color effect) • Scaling with quark number should persist • Measure of d.of. By mean of thermal radiation -> direct probe of lQCd equation of state • new universal QCD phase at high energy CGC ? (-> LHC • … It will take a lot of other Raimondo Anni Nuclear Physics School…

  45. Back-up

  46. Energy Scan GKV,PRC71 @62GeV without changing any coalescence parameter! p+/pincrease by 20% p-/pdecrease slight decrease Depends on the balance Between jet-quenching And radial flow LHC A wider range for Reco is envisaged Fries et al, EPJ(2005)

  47. Open Heavy Flavor to see Hidden Flavor J/Y & Y <-> D,B common underlying HQ distribution

  48. J/Ysuppression m + m- 6% cc bound state, MY= 2.9 GeV e+e- 6%

  49. Quarkoniumsuppression 4Tc Tc Coulomb -> Yukawa • In a QGP enviroment:(Matsui-Satz ‘86) • Color charge is subject to screening of the medium • -> qq interaction is weakened (short range) • Linear string term vanish in the confined phase • s(T) -> 0 deconfinement (long range) s-> 0 doesn’t mean no bound !

  50. Screening Effect • Abelian • Non Abelian One loop pQCD Bound state TBound is not Tc ! • Associated suppression of • charmonium resonances Y’, cc , … as a “thermometer”, like spectral lines for stellar interiors

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