1 / 34

Heavy Quark Dynamics and hadronization in the QGP

Heavy Quark Dynamics and hadronization in the QGP. V. Greco Universita di Catania INFN-LNS. He who knows does not speak  He who speaks does not know Lao-Tsu , Tao-te-ching, LXXXI. So Pietzmann at the end decided to make me speak twice!. Future of ALICE - CERN, 12-13 July 2011.

angelasullivan
Download Presentation

Heavy Quark Dynamics and hadronization 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 Dynamics and hadronization in the QGP V. Greco Universita di Catania INFN-LNS He who knows does not speak  He who speaks does not know Lao-Tsu, Tao-te-ching, LXXXI So Pietzmann at the end decided to make me speak twice! Future of ALICE - CERN, 12-13 July 2011

  2. Ideas about Heavy Quarks before RHIC mQ>>mq HQ not dragged by the expanding medium: - spectra close to the pp one - small elliptic flow v2 2) mQ >> mq,LQCD provide a better test of jet quenching: - Color dependence: RAA(B,D) > RAA(h) - Mass dependence: RAA(B)> RAA(D)> RAA(h) 3) QQ Quarkonium dissoved by charge screening: Thermometer Wiedmann, Dainese,.. cc, J/Y, cb, Y, … More binding smaller radius higher temperature

  3. Problems with ideas 1 & 2 q q Large elliptic Flow Strong suppression S. Wicks et al. (QM06) N. Armesto et al., PLB637(2006)362 • Radiative energy loss not sufficient • Charm seems to flow like light quarks Heavy Quark strongly dragged by interaction with light quarks pQCD does not work may be the real cross section is a K factor larger?

  4. Charm dynamics with upscaled pQCD cross section Diffusion coefficient Fokker-Plank for charm interaction in a hydro bulk scattering matrix Multiplying by a K-factor pQCD data data Moore & Teaney, PRC71 (2005) It’s not just a matter of pumping up pQCD cross section: too low RAA or too low v2

  5. RAA and v2 correlation No interaction means RAA=1 and v2=0. More interaction decrease RAA and increase v2 RAA “generated” earlier than v2 A typical example The relation between RAA and time is not trivial and depend on how one interact and loose energy with time. This is general, see also tomorrow talk for light quarks

  6. _ _ “D” q q “Light”-Quark Resonances c c 1.4Tc [Asakawa+ Hatsuda ’03] Indications from lQCD Spectral Function J/y (p = 0) disappears around 1.7 Tc J/Y We do not know what is behindr(w): bound states, resonances, … cq does not undergo a free scattering, but there are remants of confinement!? Look at the scattering with resonant states Van Hees, Rapp, PRC70(2005) Asakawa There can be Qq (D-like) resonant scattering!?

  7. Equilibration time pQCD QGP- RHIC “D” The first (good) model of Resonances As first test: a NR effective lagrangian: 2 parameters: GD , mD Van Hees, Rapp, PRC71(05) • Assuming F field pseudo/scalar • + axial/vector “D-like” mesons • [chiral + HQ(spin) symmetry] • cross section ISOTROPIC, • effective for thermalization • t eqdown to 5 fm/c at RHIC ! Ok, but can it describe RAA and v2? Van Hees, Greco, Rapp, PRC73(06)

  8. Can we get a quantitative hint from lQCD? Do the resonances really exist?

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

  10. Drag Coefficient from lQCD-V(r) Opposite T-dependence of g not a K-factor difference Drag coefficient g= D/mT With lQCD- V(r): -> one can expect more V2 with the same RAA because there is a strong interaction just when v2 is formed. lQCD Drag coefficient pQCD General pattern. Similarly for jet Eloss if increases with lowering temperature enhances v2 with same RAA Scardina-Greco-Di Toro, PRC83(2010) ImT increase with temperature compensates for decreasing scatterer density Does it solve the problem of “too low RAA or too low v2” ?

  11. The modeling (similar in most of the models) HQ scattering in QGP Langevin simulation in Hydro bulk c,b quarks T<<mQ • Elastic pQCD • T-matrix V(r)-lQCD • (or effetive Res. Model) sQGP From scattering matrix |M|2 Hadronization Coalescence + Fragmentation c,b fragmentation coalescence Semileptonic decay RAA & v2 of “non-photonic” e (with B contamination ) K D,B e ne But now is starting the new ERA: Dainese QM11

  12. T-matrix calculation vs PHENIX data One can get both RAA and v2 with no free tunable parameters: Essential at LHC the possibility to disentangle B and D New data • Uncertainties: • parametrization of V(r) • (quite small) • extraction of V(r) (U vs F) • (main issue) Hees-Rapp-Greco, PRL100 (2008)

  13. Different models can reproduce at least the RAA with very different RAA for D and B. Not clear the can reproduce also the v2! ( I think they can’t) Vitev’s model B at some pt even more suppressed! Uncertainties coming also from the b/c ratio vs. pt In the pQCD-HTL, Beraudo B are much less suppressed, In the Res. model between the two. What is correct?

  14. ? Impact of hadronization mechanism Impact of hadronization • Coalescence increase • both RAA and v2 • toward agreement with data • resonant states naturally merging into • a coalescence mechanism Hees-Mannarelli-Greco-Rapp, PRL100 (2008) fq from p, K Greco,Ko,Levai - PRL90 add quark momenta

  15. From RHIC to LHC? 2007 prediction BULK PARAMETERS for min. bias. (b=7fm) - dNch/dy=1400 for 0-10% central very close to Pb+Pb 2.76 ATeV - Tinit= 3 Tc + final radial flow bmax=0.68 HEAVY QUARK DISTRIBUTIONS - dN/d2pT of b,c from PYTHIA (ALICE P.P.R.-JPG32) Calculations with effective resonance model - PRC73 (2006) but resonances switched-off for T>2Tc for charm very similar to T-matrxi VlQCD ofPRL100(2008)

  16. Prediction for LHC (not exactly at the same %) Shadowing not included A. Dainese QM11 D0ALICE 0-20% D+ALICE 0-20% Shadow(EPS09) B should be more quenched in the T-matrix approach: more binding than D! Data more central (b~ 5 fm) than Theory (b=7 fm) -> lower theory band by 15% Van Hees, Greco, Rapp, 0709.4452 [hep-ph] NPA805 (2008) Last Call for prediction, JPG35(2008) 054001 Based on the PRC73(2006) Res. model similar to T-matrix VlQCD of PRL100(2008)

  17. Successfull predictions at both • RHIC but uncertainties due to single e convolution • + too large statistical error data • + the doubt of a baryon Lc enhancement (like for L/K) • has been risen -> simulate a suppression • - LHC still low resolution data and no v2 We still don’t know too much and have not drawn any conclusions

  18. coal. coal.+ fragm. G = 0.75 GeV Baryon contamination due to coalescence … !? P. Soresen, nucl-ex/0701048, PRC (07) G. Martinez-Garcia et al., hep-ph/0702035 PLB(08) Apparent reduction if Lc/D ~1 due to different branching ratio - Effect at pt~2-4 GeV region were it is more apparent the coalescence effect) • Explanation for large v2e : v2Lc > v2D Some coalescence model predict a much larger enhancement… possibility to reveal diquark correlations? Heavy-Flavor and jet quenching- Workshop, Padova 29-9-2005

  19. Main reason for a much reduced coalescence effect: • at variance with the light quark case you don’t add equal momenta • pu~ pc*mu/mc + different slope of the spectra • So there is not an enhancement equivalent to the light quark one : • do you believe to my coalescence model? • if we will observe Lc/D =1 ? What mechanism is behind it? Hadronization • in the QGP is different respect to vacuum one, but how it works? • the v2 of Lc is enhanced according to QNS scaling? (that is not 3/2 v2D) Lc/D measurement not well determined even in pp ( at FERMILAB) at least in PRL 77(1996) 2388

  20. The long standing issue of Quarkonia Suppression Y= cc, J/Y, cb, Y, … More Quarkonia dissolved with increasing energy density!? The Quarkonium Yield involves (problems with ideas 3): • Tdiss(Y) distruction and absence of formation at T> Tdiss • Ginel (Y) formation and destruction (gY-> cc , gY-> ccg) • Regeneration component as Ncc increase (sizeable at RHIC)

  21. Two opposite scenarios & all the intermediate ones Trying to sinthetize about 100 papers and 25 years … in 1 slide • STRONG BINDING: • Tdiss~ 2Tc negligible suppression of J/Y • SPS & RHIC similar because in both • only absence of cc , Y’feedown • 2) WEAK BINDING: • Tdiss~ 1.2 Tc strong suppression increasing with energy • SPS & RHIC similar because at RHIC • regeneration compensates (it was a prediction!) A way out could be to look at Open Heavy Flavor to see Hidden Heavy Flavor?

  22. Quarkonium <-> Heavy-Quark Open Flavor Going beyond J/Y yield thanks to the strong charm collective dynamics distinguish primordial from cc coalescence: - softer pT spectra of J/Y <-> dN/dpT of D (partially observed) - Large elliptic flow v2(J/Y)<-> v2(D) ? Idea is simple but there are quite some twists … Hidden Greco, Ko, Rapp-PLB595(04)

  23. Quarkonium <-> Heavy-Quark Elliptic Flow • V2c=V2q +100% recombination + • all at freeze-out [1] • V2c realistic+100% recombination + • all at freeze-out [2] [3] • V2c realistic+100% recomb + • not at f.o. [4] • 100% primordial J/Y Rapp, Blaschke, Crochet, Prog.Part.Nucl.Phys.65(2010) [1] V. Greco, C.M. Ko, R. Rapp, PLB 595(04), 202. [2] L. Ravagli, R. Rapp, PLB 655(07), 126. [3] L. Yan, P. Zhuang, N. Xu, PRL 97(07), 232301. [4] X. Zhao, R. Rapp, 24th WWND, 2008. [5] Y. Liu, N. Xu, P. Zhuang, NPA 834 (06), 317. Some remnant of the signal, but At LHC the regeneration component should dominate …

  24. Suppression-regeneration models Regeneration Zhao and Rapp, arXiv:1008.5328 Yuan, Xu, Zhuang, PRL97(2006) At 20-60% small regeneration component even decreasing with pT

  25. 7.8fm 20-60% MB MB 7.8fm 20-40% 7.8fm J/y elliptic flow v2 Zebo Tang, USTC STAR Preliminary QM2011 Disfavor coalescence from thermalized charm quarks, [1] V. Greco, C.M. Ko, R. Rapp, PLB 595, 202. [2] L. Ravagli, R. Rapp, PLB 655, 126. [3] L. Yan, P. Zhuang, N. Xu, PRL 97, 232301. [4] X. Zhao, R. Rapp, 24th WWND, 2008. [5] Y. Liu, N. Xu, P. Zhuang, NPA, 834, 317. [6] U. Heinz, C. Shen, priviate communication. Not really in disagreement with the suppression-regeneration model but against the idea of all J/Y formed thermally at freeze-out (stat. model) may be… But need more central and more precise, again high resolution! What about vn of J/Y have we explored the power of the vn analysis?

  26. For Quarkonia Agnes Mocsy at QM11 stressed the main warning valid also for open heavy flavor: Agreement in low resolution does not imply high energy resolution

  27. To be quantitative is the quality of knowelege! We have still to disentagle this and we have a knoweledge of QGP?

  28. Triggered angular correlations for heavy quarks f f f Near-side Near-side Near-side D, Lc g-radiation Resonant scattering • Unique to heavy quark : • Tag the heavy hadron distinguishable from the gluon wave • -> away heavy jet cannot be reabsorbed, where it goes • Angular correlation of jets sensitive to quenching mechanism • ->radiative vs HTL-pQCD vs resonant (calculation needed) More complicated to what it seems, to be investigated…

  29. General Message to prove experimentally the ideas envisaged theorethically - To have a quality of knoweledge need a measurement of both RAA and V2 - To understand heavy flavor interaction and hadronization need both baryon and meson up to 15-20 GeV. • Heavy Quarks : • pt< 6-8 GeV understanding if there is a resonant scattering, this • can provide a link to lQCD and may provide and answer to: • Is the QGP the one of lQCD? • pt>8 GeV understand pQCD in medium interaction • - understanding heavy quark hadronization

  30. Enhancement of J/Y at LHC!? Pure statistical model at Tc + corona effect Including both suppression and regeneration during all the evolution Rapp R., X. Zhao, arXiV:1102.2194[hep-ph] A. Andronic, P. B-M., et al., NPA 789 (2007)

  31. Heavy Quarks dragged by the medium? • Specific of Heavy Quarks • - mc,b >> LQCDproduced by pQCD processes (out of equil.) • mc,b >> T0 no thermal production • teq >tQGP >> tq,g carry more information • mc,b>>T -> q2<<m2 Brownian motion • q0<< |q| Concept of potential V(r) <-> lQCD Indirect measurement from semileptonic decay D(cq)->Ken came as a surprise Strong suppression Large elliptic Flow

More Related