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V. Greco Universita’ di Catania, Italy INFN-LNS

Light and heavy quark coalescence In Heavy-ion collisions. V. Greco Universita’ di Catania, Italy INFN-LNS. ?. Work done in collaboration with Van Hees, Ko, Levai, Rapp. Zimanyi 75 Memorial , July 2007 – Budapest (Hungary). First proceedings on QGP I looked at…. Before instead

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V. Greco Universita’ di Catania, Italy INFN-LNS

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  1. Light and heavy quark coalescence In Heavy-ion collisions V. Greco Universita’ di Catania, Italy INFN-LNS ? Work done in collaboration with Van Hees, Ko, Levai, Rapp Zimanyi 75 Memorial , July 2007 – Budapest (Hungary)

  2. First proceedings on QGP I looked at… Before instead I was working on RMFT “In the ALCOR model we assume that just before the hadronization the dense matter can be described as a mixture of dressed up, massive quarks andantiquarks. The effetive mass of the gluons at this point is much larger than that of the quarks [9], consequently the gluon fission into quark-antiquark pairs is enhanced and massive gluons disappear from the mixture.” [9] Heinz & Levai, PRC57

  3. Hadronization mechanism & QGP structure Light Hadrons and intermediate pT • Modification of hadronization mechanism • coalescence + fragmentation (RAA&v2 Bar. – Mes.) • Robustness – developments - open issues Outline Relevance of Coalescence in the Heavy-Quark sector • presence of heavy-light Qq resonances (lQCD) • Heavy quark thermalization • RAA –v2 correlation of single e • link J/Y – D : one underlying HQ distribution • From RHIC to LHC (new QGP phase)?! • SimilarRAA & v2 proof of Qq resonances in the RHIC-QGP

  4. Nuclear Modification Factor In-medium Non-abelian energy-loss • Strong (Flat) suppression explained by jet quenching • Proton not suppressed ?!

  5. H Parton spectrum Surprises… Baryon/Mesons Coalescence Baryon Au+Au Coal. Meson p+p Fragmentation PHENIX, PRL89(2003) In the vacuum p/p ~ 0.3 due to Jet fragmentation Use medium and not vacuum More easy to produce baryons Hadronization has been modified pT < 4-6GeV !? Greco, Ko, Levai, PRL 90 –PRC68

  6. Phase-Space Coalescence T=170 MeV ET ~ 730 GeV T ~ 170 MeV b(r)~ 0.5 r/R quenched soft hard e ~ 0.8 GeVfm-3 dS/dy ~ 4800 L/l=3.5 P. Levai et al., NPA698(02) 3D geometry with radial flow space-momentum correlation just overlap of fq with wave function • fqinvariant parton distribution function • thermal with radial flow(b=0.5r/R) • quenched minijets (GLV- L/l = 3.5) fHhadron Wigner function Dx = 1/Dp Bulk matter consistent with hydro, experiments, ec p,r,w,K,K*,p,D,L,S...

  7. Baryons vs Meson r-> pp TAMU DUKE v2q fitted from v2p TAMU OREGON

  8. Fries et al., PRC68 Meson & Baryon Spectra Au+Au @200AGeV (central) sh L/K • Proton suppression hidden by coalescence! Greco-Ko-Levai, PRL90 (03)202302 PRC68(03) 034904 R. Fries et al., PRL90(03)202303 PRC68(03)44902 Hwa and Yang, PRC66(02)025205 ReCo dominates up to 4-6 GeV/c; fragmentation and energy loss takes over above.

  9. A message from the early stage PHENIX, PRL (07) Coalescence scaling Enhancement of v2 • nq - not a mass effect • Most of flow is partonic z y x v2 develops t<5fm Hydro & cascade x - p correlation neglected narrow wave function Molnar and Voloshin, PRL91 (2003) baryons mesons x-p correlation in Greco-Ko-Levai still small scaling violation

  10. Ok, but this is really too naive… (!?) already included Greco-Ko-Levai, PRC68 & 70 (less important at high pT) high pT no problem … but at lower pT is not so drammatic • Resonances • Wave function finite width • Gluons • ALCOR, TAMU-coalescence : mass suppressed, splitting, quark dressing • Higher-Fock state, Fries-Muller-Bass, PLB618 (05) • 4) Energy Conservation • not large 17% in PRC68, resonances decay & v2 • Ravagli-Rapp arXiv:0705.0021 for v2(KET) • 5)Entropy Conservation • 15% like energy – Dynamical coalescence V(r,T) • 6) Relation to jet-like correlations • Fries et al.,PRL94 but need of transport description • 7) Space-momentum correlations affect v2 scaling • (Pratt-Pal PRC71, Molnar nucl-th/0408044, Greco-Ko nucl-th/0505061 ) • (At LHC they will still be so nice ?!)

  11. w.f. + resonance decay p from K & p * Effect of Resonances & wave function K, L, p …v2 not affected by resonances! p coal. moved towards p data Greco-Ko, PRC 70 (03)

  12. About Energy & Entropy … • On v2 it is mainly a shift in pt ->KET • v2 pions from rho decay (Greco-Ko-Levai, PRC68&70) • Q value effect in a Boltzmann approach • (Ravagli-Rapp, arXiv:0705.0021 [hep-ph] ) • Entropy- Energy Conservation • 15% violation, No factor 2 : • resonances • mass of the particle • degeneracies Greco-Ko-Levai, PRC68 But, the energy is not conserved ! Dynamical coalescence with interaction effects can conserve the entropy …

  13. Deeper questions… and difficult answers • Dynamical coalescence (no sudden f.o. - Molnar-QM05) • Where is confinement ? • V(r,T) (beyond sudden approx.) especially for heavy quarks - lQCD • 3) How to go from thermal to chiral masses? • Although thermal quark mass does not breal chiral Symmetry and similar magnitude • of both quantities near Tc may facilitate the formation of hadrons from 2- and • 3-quark clusters ( Heinz and Levai, PRC57). • 4) Quasiparticle with spectral function • quark mass distribution (Zimanyi-Birò-Levai, JPG31 (05) 771) • -> good p,p specra and ratio

  14. 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 (change of soft scale) • Universal elliptic flow (dynamical quarks “visible”): • carried by quarks • enhanced by coalescence Fries, Greco, Lacey, Sorensen - Ann. Rev. Part. Sci. (2008) What happens to heavy quarks?

  15. Some years ago… V2q from p, p, K, L Flow mass effect v2D 5% no c interaction but S. Kelly,QM04 V2 of electrons Greco-Ko-Rapp, PLB595 (04) 202

  16. RAA , v2 of single e -pQCD 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 lQCD resonant (bound) states persist for QQ and qq -> Qq (D-like) resonant scattering

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

  18. Open-Charm Resonances in QGP • effective model with pseudo/scalar • + axial/vector “D-like” mesons • [chiral + HQ symmetry] with dimensional regularization or form factors • cross sectionISOTROPIC • more microscopic • from lQCD potential+many-body • [Mannarelli et al.,in preparation] Ok, but can it describe RAA and v2? • t eqdown to 5 fm/c at RHIC !

  19. The model Hard production PYTHIA (PDF’s + pQCD ) c,b quarks HQ scattering in QGP Langevin simulation in Hydro bulk sQGP Hadronization Coalescence + Fragmentation c,b K D,B Semileptonic decay RAA & v2 of “non-photonic” e e ne

  20. Charm reaching thermalization?! Pythia Therm+Flow

  21. Single-Electronv2andRAAat RHIC coalescence + fragment. fq from p, K Greco,Ko,Levai - PRL90 Hees, Greco, Rapp - PRC73 pQCD Reson. • Uncertainty: • better estimate of B/C contribution • Improvements: • include radiative E-loss • resonances from lQCD – potential model • no-sudden coalescence (full transport) • resonant scatteringmore effective forRAA – v2correlation • coalescenceincreases bothRAAandv2(anti-correlation)

  22. No feed-down No direct contr. J/Y coal. Quarkonium <-> Heavy-Quark • Till now we have looked only at J/Y yield, but thanks to such a strong collective dynamics … • Regeneration is revealed in : • - pt spectra • elliptic flow v2Y from v2D : measure of Ncoal/NINI Greco, Ko, Rapp PLB595(2004) Tdiss(pT) decrease – AdS Liu et al. hep-ph/0607062 Coalecence only pT- Quarkonia from regeneration consistent with Open!? Suppression only

  23. From RHIC to LHC? For min. bias. Hydro bulk dN/dy=1100 Tinit= 3 Tc Radial flow bmax=0.68 V2q light quark =7.5 % (hydro or numerology) v2q(pT) from a cascade [VG, Colonna, Ferini, Di Toro] Resonances off T>2Tc

  24. 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!

  25. 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 Warning! Radiative energy loss to be included!

  26. Summary • Coalescence from a bulk consistent with exp. and hydro • Yields, ratios, D-fluctuations • RAA, Rcp,V2/nq vs pT • Beyond naïve coalescence -> better data description • 3D, resonances, wave function, Fock states, energy conservation • RAA - v2e anti-correlation for HQ entails: - presence of Q-q resonances (lQCD) • Similar RAA & v2 at RHIC- LHC: - if from RHIC to LHC a new QGP phase is created ! • Consistency of D and J/Y with one underlying distribution ?! • better insight into coalescence at low pT– V(r,T) 2-3 body phase-space behind hadronization Relevance of Coalescence in the Heavy-Quark sector

  27. Back up slides

  28. coal. coal.+ fragm. G = 0.75 GeV Baryon contamination due to coalescence … P. Soresen, nucl-ex/0701048 G. Martinez-Garcia et al., hep-ph/0702035 • Contamination of Lc in single e : • enhance v2e: v2Lc > v2D • enahencement modest + BRe 4.5% • but if one can verify those prediction … Apparent reduction if Lc/D ~1 consistent with RHIC data (pt~2-4 GeV) Heavy-Flavor and jet quenching- Workshop, Padova 29-9-2005

  29. Thermalization w “D”-Mesons Cross section Equilibration time pQCD QGP- RHIC “D” Isotropicangular distribution sres essential for thermalization What is the RAA and v2 ? Transport approximated Fokker-Plank equation Background not affected by heavy quarks

  30. Heavy-Flavor Baseline Spectra at RHIC Single-Electron Decays D-Mesons • bottom crossing at 5GeV !? • strategy: fix charm with D-mesons, • adjust bottom in e±-spectra

  31. Inclusion of radiative E-loss w/o gluon radiation I. Vitev, A. Adil, H. van Hees, hep-ph/0701188 Improve treatment of fluctuations (not Gaussian) Include hadronization: coal+ fragmentation

  32. RAA & v2 for D/B mesons at LHC • D and B via coalescence+ fragmentation! • coalescence leads to increase both RAA and v2 • resonant scattering factor 3 in v2

  33. What happens at lower energy –RHIC @62? Uncertainties: amount of quenching, bulk properties (ET, mb,..), p fragmentation function Without changing any coalescence parameter! p+/pincrease by 20% p-/pdecrease slight decrease Greco ,Ko, Vitev - PRC71 Balance between fragmentation (w quenching) and coalescence

  34. What happens at higher energy - LHC? • Uncertainties: • - radial flow (b=0.65-075) • jet quenching • What about the v2 ? • we will see the scaling? • r-p correlation will be so nice at LHC? Fries, Muller, EPJ C34:S279 (2004). Similar trend for MICOR + pQCD(quenched) P. Levai - ALICE Week- February 2007

  35. Charm reaching thermalization? Shadowing not included yet! Spectra same parameter of PPR-ALICE Pythia Therm+Flow • LHC spectra considerably harder ! • At Tc charm nearly thermalized • Resonances switched-off above 2 Tc

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