1 / 23

Olena Linnyk

Charmonium dynamics in heavy ion collisions. Olena Linnyk. 28 June 2007. D. J/ Y. Y ‘. c C. D bar. Charmonium production vs absorption. Hadronization. Initial State. time. Freeze-out. Quark-Gluon-Plasma ?. Transport models.

fay-cantrell
Download Presentation

Olena Linnyk

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. Charmonium dynamics in heavy ion collisions Olena Linnyk 28 June 2007

  2. D J/Y Y‘ cC Dbar Charmonium production vs absorption Hadronization Initial State time Freeze-out Quark-Gluon-Plasma ? Transport models Microscopical transport models provide the dynamical description of nonequilibrium effects in heavy-ion collisions

  3. Basic concepts of Hadron-String Dynamics • for each particle species i (i = N, R, Y, p, r, K, …) the phase-space density fifollows the transport equations • with the collision terms Icoll describing: • elastic and inelastic hadronic reactions • formation and decay of baryonic and mesonic resonances • string formation and decay(for inclusive production: BB->X, mB->X, X =many particles) • Implementationof detailed balance on the level of 1<->2 and 2<->2 reactions (+ 2<->n multi-meson fusion reactions) • Off-shell dynamics for short living states BB <-> B´B´, BB <-> B´B´m, mB <-> m´B´, mB <-> B´

  4. Degrees of freedom in HSD • hadrons - baryons and mesons including excited states (resonances) • strings – excited colour singlet states (qq - q) or (q – qbar) • Based on theLUND string model • & perturbative QCDvia PYTHIA • leading quarks (q, qbar) & diquarks • (q-q, qbar-qbar) • NOT included in the transport modelspresented here: • no explicitparton-parton interactions(i.e. between quarks and gluons) outside strings! • noQCD EoSfor partonic phase under construction: PHSD – Parton-Hadron-String-DynamicsW. Cassing arXiv:0704.1410

  5. Charmonium production • Hard probe ->binary scaling!

  6. Charmonium production in pN sJ/Yexp = sJ/Y + B(cc->J/Y)scc + B(Y‘->J/Y) sY‘

  7. Regeneration At SPS recreation of J/Y by D-Dbar annihilation is negligible But at RHIC recreation of J/Y by D-Dbar annihilation is strong!

  8. Charmonium absorption Charmonium is absorbed by : • Scattering on nucleons (normal nuclear absorption, as in pA) • Interaction with secondary hadrons (comovers) • Dissociation in the deconfined medium (suppression in QGP)

  9. = NA50 (QM2002): Anomalous absorption of J/Y in very central Pb+Pb Discovery of QGP !? Normal absorption

  10. Digal, Fortunato, Satz hep-ph/0310354 cC melting J/Y Scenarios for anomalous charmonium suppression • QGP colour screening • [Matsui and Satz ’86] • Comover absorption • [Gavin & Vogt, Capella et al.`97]: • charmonium absorption by low energy inelastic scattering with ‚comoving‘ mesons (m=p,h,r,...) • J/Y+m -> D+Dbar • Y´ +m -> D+Dbar • cC +m -> D+Dbar but (!) • Lattice QCD predicts (2004): J/Y can exist up to ~2 TC ! • Regeneration of J/Y in QGP at TC[Braun-Munzinger, Thews, Ko et al. `01]J/Y+g <-> c+cbar+g but (!) • Comover density and meson absorption cross sections unknown • Regeneration (D+Dbar->J/Y+m)

  11. Digal, Fortunato, Satz hep-ph/0310354 Threshold melting = geometrical Glauber model[Blaizot et al.] • Charmonia suppression sets in abruptly at threshold energy densities, where • cc is melting, • Y´ is melting, • J/Y is melting • Lattice QCD: Comover absorption Phase-space model for cc+meson dissociation cC melting J/Y e(cc) =2 GeV/fm3 e(Y´) =2 GeV/fm3 e(J/Y)=16 GeV/fm3 Inverse cross sections by detailed balance! Scenarios for anomalous charmonium suppression in HSD • QGP colour screening • [Matsui and Satz ’86] • Comover absorption • [Gavin & Vogt, Capella et al.`97]: • charmonium absorption by low energy inelastic scattering with ‚comoving‘ mesons (m=p,h,r,...) • J/Y+m -> D+Dbar • Y´ +m -> D+Dbar • cC +m -> D+Dbar but (!) • Lattice QCD predicts (2004): J/Y can exist up to ~2 TC ! • Regeneration of J/Y in QGP at TC[Braun-Munzinger, Thews, Ko et al. `01]J/Y+g <-> c+cbar+g but (!) • Comover density and meson absorption cross sections unknown • Regeneration (D+Dbar->J/Y+m)

  12. Comparison to data

  13. Pb+Pb and In+In @ 158 A GeVJ/Y In+In consistent both with threshold melting and comover absorptionscenarios; Pb+Pb indicates importance of comover interaction [E.L.Bratkovskaya et al PRC69 (2004) 054903, OL et al NPA786 (2007) 183]

  14. Pb+Pb and In+In @ 158 A GeVY´ Y´ data contradict threshold melting scenario with lQCD ed

  15. Au+Au @ s1/2=200 GeVComover absorption In comover scenario, suppression atmid-y stronger than atforward y,unlike data Space for parton phase effects [OL et al arXiv:0705.4443]

  16. Au+Au @ s1/2=200 GeVThreshold melting Neither of the two scenarios describes PHENIX data

  17. J/Y excitation function e e Comover reactions in the hadronic phase give almost a constant suppression; pre-hadronic reactions lead to a larger recreation of charmonia with Ebeam . The J/Y melting scenario with hadronic comover recreation shows a maximum suppression at Ebeam = 1 A TeV;exp. data ?

  18. preliminary Y´ excitation function e e Y´ suppression provides independent information on absorption vs. recreation mechanisms !

  19. Summary • J/Y probes early stages of fireball and HSD is the tool to model it. • Comover absorption and threshold melting both reproduce J/Y survival in Pb+Pb as well as in In+In @ 158 A GeV, while Y´ data favour comover absorption. • Neither hadronic interactions nor colour screening satisfactory describes the data @ s1/2=200 GeV for Au+Au. • Deconfined phase is clearly reached at RHIC, but a theory having the relevant/proper degrees of freedom in this regime is needed to study its properties (PHSD).

  20. E. Bratkovskaya, W. Cassing, H. Stöcker Thank you! nucl-th/0612049 arXiv:0704.1410 arXiv:0705.4443

  21. Back-up slide 1 FAIR predictions

  22. Back-up slide 2 Energy density

  23. Back-up slide 3 Rapidity

More Related