1 / 29

Heavy Flavor in the sQGP

Heavy Flavor in the sQGP. Ralf Rapp Cyclotron Institute + Physics Department Texas A&M University College Station, USA With: H. van Hees, D. Cabrera (Madrid), X. Zhao, V. Greco (Catania), M. Mannarelli (Barcelona) 24. Winter Workshop on Nuclear Dynamics

nani
Download Presentation

Heavy Flavor in the sQGP

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Heavy Flavor in the sQGP Ralf Rapp Cyclotron Institute + Physics Department Texas A&M University College Station, USA With: H. van Hees, D. Cabrera (Madrid), X. Zhao, V. Greco (Catania), M. Mannarelli (Barcelona) 24. Winter Workshop on Nuclear Dynamics South Padre Island (Texas), 09.04.08

  2. transport in QGP, hadronization 1.) Introduction • Empirical evidence for sQGP at RHIC: • - thermalization / low viscosity (low pT) • - energy loss / large opacity (high pT) • - quark coalescence (intermed. pT) • Heavy Quarks as comprehensive probe: • - connect pT regimes via underlying HQ interaction? • - strong coupling: perturbation theory becomes unreliable, • resummations required • - simpler(?) problem: heavy quarkonia ↔ potential approach • - similar interactions operative for elastic heavy-quark scattering?

  3. Outline 1.) Introduction 2.) Heavy Quarkonia in QGP  Charmonium Spectral + Correlation Functions  In-Medium T-Matrix with “lattice-QCD” potential 3.) Open Heavy Flavor in QGP  Heavy-Light Quark T-Matrix  HQ Selfenergies + Transport  HQ and e± Spectra  Implications for sQGP 4.) Constituent-Quark Number Scaling 5.) Conclusions

  4. 2.1 Quarkonia in Lattice QCD • direct computation of • Euclidean Correlation Fct. spectral function • accurate lattice “data” forEuclidean Correlator hc cc [Datta et al ‘04] • S-wave charmonia little changed to ~2Tc[Iida et al ’06, Jakovac et al ’07, • Aarts et al ’07]

  5. - In-MediumQ-QT-Matrix: 2.2 Potential-Model Approaches for Spectral Fcts. J/y s/w2 [Karsch et al. ’87, …, Wong et al. ’05, Mocsy+Petreczky ‘06, Alberico et al. ‘06, …] Y’ • bound state + free continuum model • too schematic for broad / dissolving states cont. w Ethr • Lippmann-Schwinger Equation [Mannarelli+RR ’05,Cabrera+RR ‘06] - 2-quasi-particle propagator: - bound+scatt. states, nonperturbative threshold effects (large) • Correlator: L=S,P

  6. 2.2.2 “Lattice QCD-based” Potentials • accurate lattice “data” for free energy:F1(r,T) = U1(r,T) – T S1(r,T) • V1(r,T) ≡ U1(r,T) - U1(r=∞,T) • (much) smaller binding for • V1=F1, V1 = (1-a) U1 + a F1 [Cabrera+RR ’06; Petreczky+Petrov’04] [Wong ’05; Kaczmarek et al ‘03]

  7. 2.3 Charmonium Spectral Functions in QGP withinT-Matrix Approach (lattice U1 Potential) Fixedmc=1.7GeV In-mediummc* (U1subtraction) hc hc • gradual decrease of binding, large rescattering enhancement • hc , J/y survive until ~2.5Tc , ccup to ~1.2Tc

  8. 2.4 Charmonium Correlators above Tc • lattice U1-potential, in-medium mc*,zero-mode Gzero ~ Tc(T) [Cabrera+RR in prep.] T-Matrix Approach Lattice QCD [Aarts et al. ‘07] hc cc1 • qualitative agreement

  9. _ _ q q Microscopic Calculations of Diffusion: q,g c • pQCD elastic scattering:g-1= ttherm ≥20 fm/cslow [Svetitsky ’88, Mustafa et al ’98, Molnar et al ’04, Zhang et al ’04, Hees+RR ’04, Teaney+Moore‘04] • D-/B-resonance model:g-1= ttherm ~ 5 fm/c “D” parameters: mD , GD c c • recent development: lQCD-potential scattering [van Hees, Mannarelli, Greco+RR ’07] 3.) Heavy Quarks in the QGP • Brownian • Motion: Fokker Planck Eq. [Svetitsky ’88,…] Q scattering rate diffusion constant

  10. 3.2 Potential Scattering in sQGP [Mannarelli+RR ’05] • T-matrix for Q-q scatt. in QGP • Casimir scaling for color chan. a • in-medium heavy-quark selfenergy: • Determination of potential • fit latticeQ-Qfree energy • currently • significant • uncertainty _ [Shuryak+ Zahed ’04] [Wong ’05]

  11. 3.2.2 Charm-Light T-Matrix with lQCD-based Potential Temperature Evolution + Channel Decomposition [van Hees, Mannarelli, Greco+RR ’07] • meson and diquarkS-wave resonances up to 1.2-1.5Tc • P-waves and (repulsive) color-6, -8 channels suppressed

  12. 3.2.3 Charm-Quark Selfenergy + Transport Selfenergy Friction Coefficient • charm quark widths Gc = -2 ImSc ~ 250MeV close to Tc • friction coefficients increase(!) with decreasing T→Tc!

  13. 3.3 Heavy-Quark Spectra at RHIC • relativistic Langevin simulation in thermal fireball background Nuclear Modification Factor Elliptic Flow pT [GeV] pT [GeV] • T-matrix approach ≈ effective resonance model • other mechanisms: radiative (2↔3), … [Wiedemann et al.’05,Wicks et al.’06, Vitev et al.’06, Ko et al.’06]

  14. 3.5 Single-Electron Spectra at RHIC • heavy-quark hadronization: • coalescence at Tc [Greco et al. ’04] • + fragmentation • hadronic correlations at Tc • ↔ quark coalescence! • charm bottom crossing • at pTe ~ 5GeV in d-Au • (~3.5GeV in Au-Au) • ~30% uncertainty due to • lattice QCD potential • suppression “early”, v2 “late”

  15. 3.6 Maximal “Interaction Strength” in the sQGP • potential-based description ↔ strongest interactions close to Tc • - consistent with minimum in h/s at ~Tc • - strong hadronic correlations at Tc ↔ quark coalescence • semi-quantitative estimate for diffusion constant: weak coupl. h/s ≈ 4/15 n <p> ltr=1/5 T Ds strong coupl. h/s≈ 1/4p Ds(2pT) = 1/2 T Ds  h/s≈ (2-4)/4p close toTc [Lacey et al. ’06]

  16. 4.) Constitutent-Quark Number Scaling of v2 [Molnar ’04, Greco+Ko ’05, Pratt+Pal ‘05] • CQNS difficult to recover withlocalv2,q(p,r) • “Resonance Recombination Model”: • resonance scatt. q+q → M close to Tc using Boltzmann eq. • quark phase-space distrib. from relativistic Langevin, hadronization at Tc: - [Ravagli+RR ’07] • energy conservation • thermal equil. limit • interaction strength • adjusted to v2max ≈7% • no fragmentation • KT scaling at both • quark and meson level

  17. 5.) Summary and Conclusions • T-matrix approach with lQCD internal energy (UQQ): • S-wave charmonia survive up to ~2.5Tc, • consistent with lQCD correlators + spectral functions • T-matrix approach for (elastic) heavy-light scattering: • large c-quark width + small diffusion • “Hadronic” correlations dominant (meson + diquark) • - maximum strength close to Tc ↔ minimum in h/s !? • - naturally merge into quark coalescence at Tc • Observables: quarkonia, HQ suppression+flow, dileptons,… • Consequences for light-quark sector? Radiative processes? • Potential approach?

  18. 3.5.2 The first 5 fm/c for Charm-Quark v2 + RAA Inclusive v2 • RAA built up earlier than v2

  19. 3.2.4 Temperature Dependence of Charm-Quark Mass • significant deviation only close to Tc

  20. 2.3.3 HQ Langevin Simulations: Hydro vs. Fireball Elastic pQCD (charm) + Hydrodynamics [Moore+Teaney ’04] as , g 1 , 3.5 0.5 , 2.5 0.25,1.8 • Tc=165MeV, • t ≈ 9fm/c • sgQ ~ (as/mD)2 • as and mD~gT • independent • (mD≡1.5T) • as=0.4, mD=2.2T • ↔ D(2pT) ≈ 20 •  hydro ≈ • fireball • expansion [van Hees,Greco+RR ’05]

  21. 3.6 Heavy-Quark + Single-e± Spectra at LHC • relativistic Langevin simulation in thermal fireball background • resonances inoperative at T>2Tc , coalescence at Tc • harder input spectra, slightly more suppression  RAA similar to RHIC

  22. 2.5 Observables at RHIC: Centrality + pT Spectra • update of ’03 predictions: - 3-momentum dependence • - less nucl. absorption + c-quark thermalization [X.Zhao+RR in prep] • direct ≈ regenerated (cf. ) • sensitive to: tctherm , mc* , Ncc [Yan et al. ‘06]

  23. coalescence essential for • consistent RAA and v2 • other mechanisms: • 3-body collisions, … [Liu+Ko’06, Adil+Vitev ‘06] 3.2 Model Comparisons to Recent PHENIX Data Single-e±Spectra [PHENIX ’06] • pQCD radiative E-loss with • 10-fold upscaled transport coeff. • Langevin with elastic pQCD + • resonances + coalescence • Langevin with 2-6 upscaled • pQCD elastic

  24. 3.2.2 Transport Properties of (s)QGP ‹x2›-‹x›2 ~ Ds·t , Ds ~ 1/g Spatial Diffusion Coefficient: Charm-Quark Diffusion Viscosity-to-Entropy: Lattice QCD [Nakamura +Sakai ’04] • small spatial diffusion → strong coupling • E.g. AdS/CFT correspondence:h/s=1/4p, DHQ≈1/2pT •  resonances: DHQ≈4-6/2pT , DHQ ~ h/s ≈ (1-1.5)/p

  25. Fragmentation only • large suppression from resonances, elliptic flow underpredicted (?) • bottom sets in at pT~2.5GeV 2.4 Single-e± at RHIC: Effect of Resonances • hadronize output from Langevin HQs (d-fct. fragmentation, coalescence) • semileptonic decays: D, B → e+n+X

  26. 2.4.2 Single-e± at RHIC: Resonances + Q-q Coalescence fqfrom p, K [Greco et al ’03] Elliptic Flow Nuclear Modification Factor • less suppression and morev2 • anti-correlation RAA ↔ v2 from coalescence (both up) • radiative E-loss at high pT?!

  27. Nuclear Modification Factor Elliptic Flow • resonances → large charm suppression+collectivity, not for bottom • v2 “leveling off ” characteristic for transition thermal → kinetic 2.3 Heavy-Quark Spectra at RHIC • Relativistic Langevin Simulation: • stochastic implementation of HQ motion in expanding QGP-fireball • “hydrodynamic” evolution of bulk-matterbT , v2 [van Hees,Greco+RR ’05]

  28. 2.1.3 Thermal Relaxation of Heavy Quarks in QGP Charm: pQCD vs. Resonances Charm vs. Bottom pQCD “D” • tctherm ≈ tQGP ≈ 3-5 fm/c • bottom does not thermalize • factor ~3 faster with • resonance interactions!

  29. 5.3.2 Dileptons II: RHIC [R. Averbeck, PHENIX] [RR ’01] QGP • low mass: thermal! (mostly in-medium r) • connection to Chiral Restoration: a1 (1260)→ pg ,3p • int. mass:QGP (resonances?)vs.cc → e+e-X (softening?) -

More Related