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o Overview Selected results from RHIC “light quark” jet quenching

Heavy Flavor Physics at RHIC Matthias Grosse Perdekamp U of Illinois and RIKEN BNL. o Overview Selected results from RHIC “light quark” jet quenching and elliptic flow

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o Overview Selected results from RHIC “light quark” jet quenching

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  1. Heavy Flavor Physics at RHICMatthias Grosse Perdekamp U of Illinois and RIKEN BNL • o Overview • Selected results from RHIC • “light quark” jet quenching • and elliptic flow • Energy loss of heavy quarks in media • as tool to study nuclear media formed in • heavy ion collisions.

  2. Heavy Flavor Physics at RHIC: Overview open heavy flavor production spectroscopy: Quarkonia as “Thermometer”: color screening depends on T Matsui and Satz, Phy.Lett. B 178 (1986)416 1) Energy loss in dense and hot nuclear matter 2) Tomography of DHNM 3) Reference data for quarkonia QGP? A-A • Modification of PDFs in nuclear environment (anti-) shadowing • vs new state of matter (color glass condensate) • 2) Reference data for initial state in A-A PDF(A) p/d-A QCD p-p, d-A, A-A 1) Hadronization mechanism 2) Reference data for quarkonia 1) Cross sections vs rapidity and √s 2) Vacuum energy loss vs media 3) Reference data Polarized PDFs p-p measure formation process?

  3. Polarized pp: ΔG from charm production Double spin asymmetry electron asymmetry for charm production (I. Bojak and M. Stratmann, hep-ph/0112276) • Scale dependence reduced at NLO: LO NLO

  4. Relativistic Heavy Ion Collider Design Parameters: PerformanceAu + Au p+p snn 200 GeV 500 GeV L [cm-2 s -1 ] 2 x 1026 2 x 1032 Cross-section 7 barns 60 mbarn Interaction rates 14 kHz 12 MHz RHIC Capabilities • Au + Au collisions at 200 GeV/u • p + p collisions up to 500 GeV • spin polarized protons (70%) • lots of combinations in species and energy in between

  5. physics target minimumprojection maximumprojection RHIC Running Delivered 1196 (mb)-1 to Phenix [week ago : 1060] 136 (mb)-1 last week [best week: 158] 2 x design Luminosity!

  6. Charm and J/ψ Data from RHIC • Run I, 2001 Au-Au beams at s=130 GeV • Open charm from PHENIX • Run II, 2002 Au-Au beams and p-p at s=200 GeV • Open charm and J/Y from PHENIX • Run III, 2003 d-Au, p-p at s=200 GeV • Open charm from PHENIX and STAR, J/Y from PHENIX • Run IV, 2004 Au-Au, s=200 GeV • More measurements to come

  7. STAR: Large acceptance TPC+EMC

  8. Au-Au Event in STAR

  9. PHENIX Physics Capabilities designed to measure rare probes:+ high rate capability & granularity + good mass resolution and particle ID - limited acceptance Au-Au & p-p spin • 2 central arms: electrons, photons, hadrons • charmonium J/, ’ -> e+e- • vector mesonr, w,  -> e+e- • high pTpo, p+, p- • direct photons • open charm • hadron physics • 2 muon arms: muons • “onium” J/, ’,  -> m+m- • vector meson -> m+m- • open charm • combined central and muon arms: charm production DD -> em • global detectors forward energy and multiplicity • event characterization

  10. Au-Au and d-Au events in the PHENIX Central Arms Au-Au d-Au

  11. STAR Preliminary p + p d + Au Open charm in pp: Single electrons charm cross sections (barely) agree! PHENIX PRELIMINARY =1.36 ± 0.20 ± 0.39 mb PHENIX: three methods to subtract photonic background STAR: three methods to identify electrons

  12. Consistency between electron data sets • STAR slightly above PHENIX

  13. PHENIX PRELIMINARY Does the PYTHIA “extrapolation” work? 1Phys. Rev. Lett. 88, 192303 (2002) STAR preliminary PYTHIA tuned to available data (sNN < 63 GeV) prior to RHIC results • spectra are harder than PYTHIA extrapolation from low energies • Use parametrization for Au-Au reference • Use rapidity dependence from PYTHIA to extract cross section

  14. 0 < pT < 3 GeV/c, |y| < 1.0 d+Au minbias D0+D0 Reconstruction of D mesons in dAu Collisions STAR preliminary = 1.12 ± 0.20 ± 0.37 mb from D data (1.36 ± 0.20 ± 0.39 mb with electrons)

  15. Collision Geometry -- “Centrality” Spectators Participants For a given b, Glauber model predicts Npart (No. participants) and Nbinary (No. binary collisions) 15 fmb 0 fm 0 Npart 394 0 Nbinary 1200

  16. BBC Au Au BBC Experimental Determination of Centrality ZDC ZDC ZDC: zero degree calorimeter BBC: beam-beam counter

  17. Almond shape overlap region in coordinate space Selected Results: Elliptic Flow Origin:spatial anisotropy of the system when created, followed by multiple scattering of particles in the evolving system spatial anisotropy  momentum anisotropy v2:2nd harmonic Fourier coefficient in azimuthal distribution of particles with respect to the reaction plane Outgoing particle

  18. E. Shuryak

  19. Hydrodynamic limit exhausted at RHIC for low pT particles. Large magnitude of v2 suggests highly viscous “liquid”: strongly interacting nuclear medium has been formed! Large v2 STAR v2 for charged particles Adler et al., nucl-ex/0206006

  20. Probing the nuclear medium formed: Jet Suppression charm/bottom dynamics J/Y & U direct photonsCONTROL

  21. schematic view of jet production hadrons leading particle q q hadrons leading particle Light qs and g jets as probe of the medium Jets from hard scattered quarks observed via fast leading particles or azimuthal correlations between the leading particles • However, before they create jets, the scattered quarks radiate energy (~ GeV/fm) in the colored medium • Decreases their momentum (fewer high pT particles) • Eliminates jet partner on other side Jet Quenching

  22. Quantify Nuclear Modification of Hadron Spectra 1. Compare Au+Au to nucleon-nucleon cross sections 2. Compare Au+Au central/peripheral Nuclear Modification Factor: nucleon-nucleon cross section <Nbinary>/sinelp+p AA AA If no “effects”: R < 1 in regime of soft physics R = 1 at high-pT where hard scattering dominates Suppression: R < 1 at high-pT AA AA AA AA

  23. Quantitative Agreement across Experiments Effect is real…Final or Initial State Effect?

  24. Centrality Dependence Au-Au vs d-Au Au + Au Experiment d + Au Control Experiment • Significantly different and opposite centrality evolution of Au+Au experiment from d+Au control. • Jet Suppression is clearly a final state effect. Final Data Preliminary Data

  25. Heavy Quark Energy Loss in Media • Shuryak proposed that charm quarks may suffer a large energy loss • when propagating through a high opacity plasma, leading to large • suppression of D mesons. (E. V. Shuryak, Phys. Rev. C 55, 961 (1997) • Dokshitzer and Kharzeev propose the “dead cone” effect: • Reduced gluon emission at small angles in media for heavy quarks • may lead to enhancement in D meson production. Y.L. Dokshitzer and D. E. Kharzeev, Phys. Lett. B 519, 199 (2001) 2003 Djordjevic and Gyulassy: detailed quantitative treatment of heavy quark energy loss in strongly interacting media. Predict slight suppression: 0.6-0.8! M. Djordjevic and M. Gyulassy, nucl-th/0310076

  26. Radiative heavy quark energy loss • from Magdalena Djordjevic at QM 2004 • There are three important medium effects that control the • radiative energy loss at RHIC • Ter-Mikayelian effect (Djordjevic-Gyulassy Phys.Rev.C68:034914,2003) • Transition rediation (Zakharov) • Energy loss due to the interaction with the medium Ter-Mikayelian: QCD analog to dielectric effect in electrodynamics 1) 2) 3)

  27. Centrality dependence in AuAu No deviations from binary scaling within uncertainties. Consistent with Djordjevic and Gyulassy: 10 x more data from Run 2004! 1/TABEdN/dp3 [mb GeV-2] 1/TABEdN/dp3 [mb GeV-2] pp reference pp reference 1/TAA 1/TAA 1/TABEdN/dp3 [mb GeV-2] 1/TABEdN/dp3 [mb GeV-2] 1/TABEdN/dp3 [mb GeV-2] 1/TABEdN/dp3 [mb GeV-2] 1/TAA 1/TAA 1/TAA pp reference pp reference pp reference

  28. PHENIX PRELIMINARY PHENIX PRELIMINARY PHENIX PRELIMINARY 1/TABEdN/dp3 [mb GeV-2] 1/TABEdN/dp3 [mb GeV-2] 1/TAB 1/TAB 1/TABEdN/dp3 [mb GeV-2] PHENIX PRELIMINARY PHENIX PRELIMINARY 1/TABEdN/dp3 [mb GeV-2] 1/TABEdN/dp3 [mb GeV-2] 1/TAB 1/TAB Centrality dependence in dAu Single electron spectra in dAu are in good agreement with the proton reference.

  29. Charm flow? PHENIX PRELIMINARY • is partonic flow realized? • v2 of non-photonic electrons indicates non-zero charm flow in AuAu collisions • uncertainties are large • definite answer: RUN-04 AuAu data sample!

  30. J/Y: Does colored medium screen cc ? 40-90% most central Ncoll=45 20-40% most central Ncoll=296 0-20% most central Ncoll=779 Statistics limited: Run 2004! R.L. Thews, M. Schroedter, J. Rafelski Phys. Rev. C63 054905 (2001): Plasma coalesence model for T=400MeV and ycharm=1.0,2.0, 3.0 and 4.0. L. Grandchamp, R. RappNucl. Phys. A&09, 415 (2002) and Phys. Lett. B 523, 50 (2001): Nuclear Absorption+ absoption in a high temperature quark gluon plasma A. Andronic et. Al. Nucl-th/0303036 Proton

  31. Summary • The final state produced in central Au-Au collisions at RHIC is dense and opaque and appears to have the properties of a strongly interaction liquid. • The energy loss of heavy quarks in nuclear media is an important tool to further characterize the nature of the medium produced at RHIC. • Heavy flavor production will play an important role in studying nucleon structure in d-A and polarized p-p collisions at RHIC. The experimental possibilities will be greatly enhanced by silicon vertex detector upgrades for PHENIX and STAR. We expect a significant qualitative and quantitative advance from run 2004 in understanding the nature of the matter formed in central collisions at RHIC.

  32. PHENIX: J/Ye+e- and m+m- from pp s= 3.99 +/- 0.61(stat) +/- 0.58(sys) +/- 0.40(abs) mb (BR*stot = 239 nb) • Central and forward rapidity measurements from Central and Muon Arms: • Rapidity shape consistent with various PDFs • √s dependence consistent with various PDFs with factorization and renormalization scales chosen to match data • Higher statistics needed to constrain PDFs

  33. PHENIX: J/Ye+e- and m+m- from pp • pT shape consistent with COM over our pT range • Higher statistics needed to constrain models at high pT • Polarization measurement limited

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