1 / 19

Heavy-Quark Thermalization and Resonances in the QGP

Heavy-Quark Thermalization and Resonances in the QGP. Ralf Rapp Cyclotron Institute + Physics Department Texas A&M University College Station, USA With: H. van Hees (Texas A&M), V. Greco (Texas A&M, Catania) Quark Matter 2005 Conference Budapest (Hungary), 06.08.05.

wayne
Download Presentation

Heavy-Quark Thermalization and Resonances in the QGP

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-Quark Thermalization and Resonances in the QGP Ralf Rapp Cyclotron Institute + Physics Department Texas A&M University College Station, USA With: H. van Hees (Texas A&M), V. Greco (Texas A&M, Catania) Quark Matter 2005 Conference Budapest (Hungary), 06.08.05

  2. 1.) Introduction: Single-e± Spectra pre-QM05 RAA Djordjevic etal. ‘04 jet-quench [Djordjevic etal ’04] Armesto etal.‘05 pT [GeV/c] Coalescence assuming v2(c) = v2(q) and/or jet quenching? Challenges: • dynamical origin of strong re-interactions • consistency v2 ↔ RAA • open-bottom “contamination” • induced radiation vs. elastic scattering • …

  3. Outline 2.) Baseline Spectra in p-p, d-Au Charm vs. Bottom 3.) Heavy-Quark Elastic Scattering in QGP  pQCD vs. Resonances  Brownian Motion and Thermal Relaxation 4.) Heavy-Quark and Electron Spectra at RHIC  Langevin Simulation, Hadronization RAA and v2 5.) Heavy Quarkonia  Charmonium pT-Spectra 6.)Conclusions

  4. 2.) Heavy-Flavor Baseline Spectra at RHIC Single-Electron Decays D-Mesons • bottom crossing at 5GeV !? (pQCD: ~4GeV[Cacciari etal ’05]) • strategy: fix charm with D-mesons, adjust bottom in e±-spectra

  5. 3.) Elastic Heavy-Quark Scattering in the QGP 3.1 Perturbative QCD [Svetitsky ’88, Mustafa etal ’98, Molnar etal ’04 Zhang etal. ’04, Teaney+Moore‘04] q c g c • dominated by t-channel gluon-ex in gc→gc: • Brownian • Motion: Fokker Planck Eq. scatt. rate diff. const. • e.g. T=400MeV, as=0.4  g = 0.1 fm-1 ↔ ttherm~10fm/cslow!

  6. _ _ “D” q q c c • number of D-states: • 4 per u and d, 2 for s • cross section isotropic • more microscopic → [M.Mannarelli’s talk] 3.2 Open-Charm Resonances in QGP “Light”-Quark Resonances [van Hees+ RR ’04] 1.4Tc • effective model with pseudo/scalar • + axial/vector “D-mesons” [Asakawa+ Hatsuda ’03] • parameters: mD(0)=2GeV , GD, • mc=1.5GeV, mq=0

  7. Charm vs. Bottom • tcrelax ≥ Dt(T>0.25GeV) ≈ 1fm/c • bottom does not thermalize (10%) 3.3 Heavy-Quark Thermalization Times in QGP Charm: pQCD vs. Resonances pQCD “D” • substantially smaller for • resonances

  8. 4.) Heavy-Quark and Electron Spectra at RHIC 4.1 Relativistic Langevin Simulations → stochastic implementation of heavy quarks in expanding fireball with realistic time evolution of bulkv0 , v2 [van Hees,Greco+RR ’05] Nuclear Suppression Factor Elliptic Flow • characteristic “leveling-off” • factor ~4 from resonances • pQCD elastic scatt. moderate • resonance effects substantial

  9. Elliptic Flow Nuclear Suppression Factor Minimun-Bias Au-Au 200GeV Minimun-Bias Au-Au 200GeV • coalescence increases both RAA and v2 , resonances essential • bottom contribution reduces effects • induced gluon radiation? [van Hees, Greco +RR ’05] 4.2 Single-Electron v2 and RAA at RHIC coalescence + fragment. fqfrom p, K

  10. 5.) J/y pt-Spectra in Au-Au at RHIC Quark Coalescence at Tc [Thews+Mangano ’05] [Greco,Ko+RR ’04] • total yields different by factor 3 • large sensitivity to radial flow (bt,max=0.5-0.65)

  11. 6.) Summary • “D”-meson resonances in QGP (lQCD spectral fcts., potentials) • c(b)-quark thermalization ~4(12)fm/c (elastic scattering), • (factor ~3 faster than pQCD) • Langevin simulation for RHIC + coalescence/fragmentation: • - electrons: v2≤11% , RAA≥0.45 (MinBias), • “compromised” by bottom • - predictions similar to new PHENIX data • sQGP elastic scattering (resonances) prevalent over radiation • at low / medium pt !? • (more) uncertainties: hadronic phase (lifetime), smaller mc (?), • bottom contribution, softer fragmentation • impact on quarkonia, dileptons (intermediate mass)

  12. Applications • → Schröd.-Eq. • → bound states (sQGP)! • scattering states? imaginary parts? • → Lippmann-Schwinger Equation [Shuryak,Zahed, Brown ’04] - q-qT-Matrix Quark- Selfenergy  Selfconsistency Problem [Mannarelli+RR ’05] 3.) Resonances in QGP: Microscopic Description Lattice Q-Q Free Energy [Bielefeld Group ’04]

  13. - q-qT-Matrices 3.2 Selfconsistent T-Matrix and Selfenergy [Mannarelli+RR ’05] T=1.2Tc T=1.5Tc T=1.75Tc • assume mq(gluon)=0.1GeV • transition from bound (1.2Tc) • to resonance states! • quark-width≈0.3GeV≈(2/3fm)-1 • (≈ mass ↔ liquid!?) • colored states, equat. of state? Quark Self- Energy T=1.5Tc

  14. Individual Charm- and Bottom-Electron RAA and v2

  15. 2.4.2 Langevin-Simul. at RHIC: Heavy-Quark v2 Charm-pQCD (as,mD=1.5T) Resonances vs. pQCD • hydro with Tc=165, t ≈ 9fm/c • as and Debye mass independent • characteristic “leveling-off” • factor ~4 from resonances • more sensitive to res.-coupling [Moore and Teaney ’04] [van Hees,Greco+RR ’05]

  16. 2.4.1 Langevin-Simul. at RHIC: Heavy-Quark RAA Resonances vs. pQCD Charm-pQCD (as,mD=1.5T) as , g 1 , 3.5 0.5 , 2.5 0.25,1.8 • hydro with Tc=165MeV, t ≈ 9fm/c • as and Debye mass independent • expanding fireball ≈ hydro • pQCD elastic scatt. moderate • resonance effects substantial [Moore and Teaney ’04] [van Hees,Greco+RR ’05]

  17. Coordinate Space Diffusion • ‹x2› - ‹x›2 = Dx t ≈ (5 fm)2 • ~ fireball size at Tc c-Quark Drag and Diffusion Coefficients in QGP [van Hees+RR ’04] Thermalization Times pQCD “D” • substantially smaller for • resonances

  18. J/yExcitation Function [Grandchamp +RR ’03] • QGP-regeneration dominant • sensitive to: • mc* , (Ncc )2 ↔ rapidity, √s, A same net suppression at SPS + RHIC! 4.4 Charmonium in A-A SPSRHIC Pb(158AGeV)-Pb • QGP-suppression prevalent • no “jump” in theory [Grandchamp etal. ’03]

  19. 3.4.3 Scrutinizing Charmonium Regeneration II: J/y Elliptic Flow Suppression only Thermal Coalescence at Tc [Greco etal ’04] [Wang+Yuan ’02] MB Au-Au • factor ~5 different! • transition inpt!?

More Related