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Collective Dynamics and hadronization of heavy & light quarks

Collective Dynamics and hadronization of heavy & light quarks. Collective Dynamics and hadronization of heavy quarks. V. Greco Universita’ di Catania INFN-LNS. In collaboration with H. Van Hees, R. Rapp Texas A&M University. QCD@Work , June 2007 – Martina Franca (Italy).

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Collective Dynamics and hadronization of heavy & light quarks

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  1. Collective Dynamics and hadronization of heavy & light quarks Collective Dynamics and hadronization of heavy quarks V. Greco Universita’ di Catania INFN-LNS In collaboration with H. Van Hees, R. Rapp Texas A&M University QCD@Work , June 2007 – Martina Franca (Italy)

  2. QGP structure in the Heavy Quark sector RAA & v2 -> strong interaction (sQGP) • Modification of hadronization mechanism • coalescence + fragmentation (RAA&v2 Bar. – Mes.) • presence of heavy-light Qq resonances (lQCD) • Heavy quark thermalization • relevance of Hadronization mechanism for HQ • link J/Y – D : one underlying HQ distribution Outline • From RHIC to LHC (new QGP phase) • SimilarRAA & v2 proof of Qq resonances in the RHIC-QGP

  3. Nuclear Modification Factor In-medium Non-abelian energy-loss AA If R = 1 here, nothing new going on (sum of pp collision) • Strong (Flat) suppression explained by jet quenching • Proton not suppressed ?!

  4. H Parton spectrum Surprises… Baryon/Mesons Coalescence Baryon Au+Au Coal. 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 !? But if this is true then … Greco, Ko, Levai, PRL 90 –PRC68

  5. A measure of the Pressure: Elliptic Flow Coalescence scaling Enhancement of v2 z y x py px RAA smaller v2 larger Pressure c2s=dP/de Mean free path baryons mesons Hadronization is modified Dynamical quarks are visible

  6. Highlights from the light sector • Hadronization modified by the dense medium: • massive quarks close in phase space can coalescence • hadrons at pt comes from quarks pt/n (pt kick) • 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? RAA and v2 of electron from D and B semileptonic decay

  7. 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

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

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

  10. 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

  11. Single-Electronv2andRAAat RHIC coalescence + fragment. fq from p, K Greco,Ko,Levai - PRL90 Hees, Greco, Rapp - PRC73 pQCD Reson. • resonant scatteringmore effective forRAA – v2correlation • coalescenceincreases bothRAAandv2(anti-correlation)

  12. 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) Coalecence only pT- Quarkonia from regeneration consistent with Open!? Suppression only

  13. 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 % v2q(pT) cascade [VG, Colonna, Ferini, Di Toro] Resonances off T>2Tc

  14. 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!

  15. 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!

  16. Summary • RAA - v2e correlation for HQ entails: - presence of Q-q resonances (lQCD) - Relevance of coalescence • Similar RAA & v2 at RHIC- LHC: - if from RHIC to LHC a new QGP phase is created ! • Consistency of D and J/Y @ RHIC ! - v2 (pT) decisive contribution to J/Y issues Open Flavor Heavy quarks thermalization LHC ALICE Hidden • Possible to study theQGP structure at finite T • - lQCD potential model and/or NREFT ?! Greco, Ko, Rapp-PLB595

  17. Back up slides

  18. Charm at RHIC & LHC 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 at 2 Tc

  19. Calculation of Collisional energy loss w(p,k) directed linked to the cross section g c q c [Svetitsky ’88, Braaten ’91, Mustafa etal ’98, Molnar etal ’04 Zhang etal. ’04, Teaney+Moore‘04] • dominated by t-channel gluon-ex in gc→gc: Drag & Diffusion p-indipendent scatt. rate diff. const. Transport Equation in quasi-particle approx. Expanding w(p,k) around p~k : dominated by soft scattering: (resonable for heavy quarks) Fokker-Plank equation Background not affected by heavy quarks

  20. _ _ “D” q q c c “Light”-Quark Resonances 1.4Tc [Asakawa+ Hatsuda ’03] Open-Charm Resonances in QGP lQCD [Hees-Rapp] J/Y • effective model with pseudo/scalar • + axial/vector “D-like” mesons • [chiral + HQ symmetry] • cross section isotropic • more microscopic • from lQCD potential→[in preparation] • t eqdown to 5 fm/c at RHIC ! Ok, but can it describe RAA and v2?

  21. 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

  22. 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

  23. 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

  24. 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

  25. Phase-Space Coalescence fqinvariant parton distribution functionthermal (mq=0.3 GeV, ms=0.47 GeV) with radial flow (b=0.5) + quenched minijets (L/l = 3.5, mq=0.01GeV, ms=0.175 GeV) |Mqq->m|2 depends only on the phase space weighted by wave function; npQCD also encoded in the quark masses (gluon dressing), mq=0.3 GeV, ms=0.475 GeV. fHhadron Wigner function Dx = 1/Dp ~ 0.85 fm coalescence radius parameter

  26. TAMU implementation T=170 MeV ET ~ 730 GeV b(r)~ 0.5 r/R T ~ 170 MeV quenched soft hard V ~ 900 fm-3 e ~ 0.8 GeVfm-3 dS/dy ~ 4800 L/l=3.5 P. Levai et al., NPA698(02)631 Coalescence Integral solved in a 3D geometry, with radial flow space-momentum correlation (important to fix bulk parton distribution) Locally v1, u1 … not small Coalescence on bulk matter consistent with hydro, experiments, ec

  27. Meson & Baryon Spectra Au+Au @200AGeV (central) sh 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..6 GeV/c; fragmentation and energy loss takes over above.

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

  29. Recombination with thermal masses (from LQCD) • Link to LQCD • Energy Conservation • (-> Entropy , Resonances) EOS LQCD DB V(r) Spectral function To be checked: properties of standard coalescence are preserved Input of Coalescence

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