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Soft sector: promises, promises...

Soft sector: promises, promises.  ~ 10 GeV/fm 3 >>  C (Bjorken / hydro) Early thermalization (v2 / hydro) T chem ~ T H ~ T c ~ 170 MeV  b ~ 30-40 MeV -- near baryon free  connection to lattice? further evolution (PdV work?) & expansion leading to...

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Soft sector: promises, promises...

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  1. Soft sector: promises, promises... •  ~ 10 GeV/fm3 >> C(Bjorken / hydro) • Early thermalization (v2 / hydro) • Tchem ~ TH ~ Tc ~ 170 MeV • b ~ 30-40 MeV -- near baryon free  connection to lattice? • further evolution (PdV work?) & expansion leading to... • cooling and bulk collective motion (pT spectra, v2, HBT, K-) Can we use an external probe to explore further? mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  2. Can we do the same at RHIC? scattered electron incoming electron (controlled probe) Discovery and Properties: The Ideal Experiment The first exploration of subatomic structure was undertaken by Rutherford at Manchester in 1909 using Au atoms as targets and a particles as probes. NO QGP But we can get close ……… mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  3. p+p sNN=200 GeV PHENIX PRL 91 241803 (2003) Fast Partons (Quarks & Gluons) Traversing Matter hadrons • Jets: • high-pT parton produced in a hard (high-Q) scattering process • Calculable in QCD (at high-pT) • partons fragment into many correlated white hadrons • emitted in a cone • created early in the collision quark quark hadrons leading particle (highest-p particle) mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  4. The tail probes the bulk Fate of jets in heavy ion collisions? idea: p+p collisions @ same sNN = 200 GeV as reference p p ?: what happens in Au+Au to jets which pass through medium? ? Au+Au mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  5. 200 GeV 0 RAA PHENIX (and all others) PRL2003 Nuclear overlap model to calculate # incoherent NN collisions (no shadowing etc) RAA = (# seen in nuclear collision) / (# expected) (PHENIX notation: f=centrality cut) The Ubiquitous RAA… 5x fewer high pT particles than “expected” in AuAu • Required checks: • saturation (initial-state) effect? mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  6. d Au ? Au Au Au+Au The control experiment: d+Au, 2003 mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  7. Centrality Dependence Au + Au Experiment d + Au Control Experiment • Dramatically different and opposite centrality evolution of Au+Au experiment from d+Au control. • Jet Suppression is clearly a final state effect. mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  8. 200 GeV 0 RAA PHENIX (and all others) PRL2003 Nuclear overlap model to calculate # incoherent NN collisions (no shadowing etc) RAA = (# seen in nuclear collision) / (# expected) (PHENIX notation: f=centrality cut) The Ubiquitous RAA… 5x fewer high pT particles than “expected” in AuAu • Required checks: • saturation (initial-state) effect? • d-Au null result • hard scattering rates understood? • measure “robust” hard processes mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  9. Direct photons visible because0 is suppressed!! PHENIX Hard non-mesonic (“direct”) photons & non-photonic (“charming”) electrons • Created in earliest, hardest parton scatterings & conserved thereafter • binary scaling √ • (probably some Cronin inside errors) • probe-once-created and creation itself in AA are “calibrated” (better than d-Au) PHENIX QM04 NB: pT-integrated PHENIX 2004 mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  10. 200 GeV 0 RAA PHENIX (& all others): PRL 2003 The Ubiquitous RAA… 5x fewer high pT particles than “expected” in AuAu • Required checks: • saturation (initial-state) effect? • d-Au null result • hard scattering rates understood? • measure “robust” hard processes • charm / direct  follow Nbinary • Accepted view • final state effect is partonic energy loss in color-charge-dense(not necc. deconfined) medium •  = 15 GeV/fm3 @  = 0.2 fm • ~ consistent w/ BJ and hydro… mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  11. is it “jet” quenching? Go beyond leading particles 200 GeV 0 RAA PHENIX (& all others): PRL 2003 The Ubiquitous RAA… 5x fewer high pT particles than “expected” in AuAu • Required checks: • saturation (initial-state) effect? • d-Au null result • hard scattering rates understood? • measure “robust” hard processes • charm / direct  follow Nbinary • Accepted view • final state effect is partonic energy loss in color-charge-dense(not necc. deconfined) medium •  = 15 GeV/fm3 @  = 0.2 fm • ~ consistent w/ BJ and hydro… mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  12. STAR Au+Au event Beyond leading particles STAR p+p event find this… …in this mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  13. trigger Jets via azimuthal correlations STAR p+p event • trigger: highest pT track, pT>4 GeV/c • Df distribution for 2<pT<pTtrigger • normalize to number of triggers PRL 90, 082302 mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  14. STAR Au+Au event Jets via azimuthal correlations Try the same in Au-Au (large combinatorics)… mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  15. Azimuthal distributions in Au+Au pedestal and flow subtracted PRL 90, 082302 • Peripheral collisions: • very similar to p+p • Central collisions: • strong suppression • of away-side jet mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  16. midcentral (20-60%) collisions nucl-ex/0407007 Further geometric detail Suppression depends on pathlength thru medium This analysis: cannot be initial state effect mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  17. anything new in-between? • Probes of the system (hard) • interesting results • important open questions • System itself (soft) • interesting/important results • important open questions If we bridge the gap (“firm”)? ? mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  18. mass systematic v2 generated by anisotropic energy loss? symmetry, thermal smearing Connecting the sectors soft-firm connection: v2 • hydro breaks down above~ 2 GeV/c (expected) • mass systematic meson/baryon systematic? • definitely not hydro! P. Sorensen, SQM04 mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  19. v2 generated by anisotropic energy loss? Connecting the sectors soft-firm connection: v2 • hydro breaks down above~ 2 GeV/c (expected) • mass systematic meson/baryon systematic? • definitely not hydro! hard-firm connection: RAA PID-differential meson/baryon systematic! BUT!… mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  20. PRL 92 (2004) 052302 PRL 92 (2004) 052302 Non-hydro / non-E origin of firm v2? meson/baryon (i.e. constituent quark number) systematics suggest… coalescence (“recombination”) of already-flowing (!!) partons (*) *well, constituent quarks mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland P. Sorensen, SQM04

  21. Baryons compete with mesons A growth industry... … for a thermal source Fragmentation wins out for a power law tail Many model variants Lin, Molnar, Pratt, Fries, Bass, Mueller, Ko, Das, Levai, Hwa, Greco, Voloshin, Nonaka… Many schemes, all describe “anomalous” B/M, RAA, v2 But, data themselves (IMHO) clearly indicate exciting, collective partonic behaviour Hope for a “hadronization testbed”? B. Mueller TBS05 mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  22. “calibrated” probes: final state effect color-dense medium new at RHIC (?) sensible geometrical systematics  ~ 10 0 baryon / meson systematics unexpected! (constituent?) partonic collectivity?! [possibility to test hadronization mechanisms?] bulk, collective system  ~ 10 0 Tch~ TC ~ 170 MeV; b~30 MeV Tkin~100 MeV, flow~0.7c high pT hydro works early thermalization. sensitivity to early-stage EoS mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  23. Open Issues mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  24. soft sector questions • hydro and v2 • hydro “limits” ? • EoS - does Lattice really work • RHIC HBT “puzzle” • puzzle #1: failure of (otherwise-successful) dynamical models • puzzle #0: generic “failure” - no sign of P.T. mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  25. hydro “limit”? we have a bad history in RHI mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  26. Finally, we understand it! Gyulassy 1995 Motivation Formalism Experiment Trends Models Just one event! Trends, soft sector, and RHI history 6 decades of E/A (2 decades of sNN) Art’s talk. Compiled by A. Wetzler (2005) mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  27. dN/dy Kolb, Sollfrank, Heinz, PRC62 054909 (2000) hydro “limit”? mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  28. p1 q p2 Disintegration timescale Relative momentum between pions is a vector  can extract 3D shape information Rlong – along beam direction Rout – along “line of sight”  increases with emission timescale Rside –  “line of sight” Rout Rside mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  29. Disintegration timescale - expectation 3D 1-fluid Hydrodynamics Rischke & Gyulassy, NPA 608, 479 (1996) with transition with transition “” “” • Long-standing favorite signature of QGP: • increase in , ROUT/RSIDE due to deconfinement  confinement transition • expected to “turn on” as QGP energy threshold is reached mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  30. 8 8 6 6 RO (fm) 4 4 RS (fm) 1.5 1.25 RO / RS 1.0 increasing collision energy RHIC Disintegration timescale - observation • no threshold effect seen • RO/RS ~ 1 mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  31. Disintegration timescale - observation • no threshold effect seen • RO/RS ~ 1 • toy model calculations suggest very short timescales F. Retiere & MAL, PRC 70 (2004) mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  32. Heinz & Kolb, hep-ph/0204061 An important space-time “puzzle” at RHIC - actively under study Disintegration timescale - observation • no threshold effect seen • RO/RS ~ 1 • toy model calculations suggest very short timescales • rapid, explosive evolution • too explosive for “real” modelswhich explain all other data N() mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  33. STAR PRL93 (2004) 012301 central collisions • estimate INIT from Glauber • from asHBT: mid-central collisions peripheral collisions Shape evolution: never goes in-plane? Measured final source shape STAR, PRL93 012301 (2004) Expected evolution: ? mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  34. firm/hard sector questions • firm • entropy issue (I really don’t care - theorists will work it out) • what is a “dynamical constituent quark”? • hard • no consistent energy loss scenario describing geometrical systematics of energy loss (Miodosewski/Tannenbaum) • is charm quenched? What about dead cone?-- can it be gluon radiation? • both issues do we really understand the energy loss mechanism? • if not, how can we say we probe color density • and, if so, what can we say besides color density (e.g. deconfined or not) mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  35. mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  36. mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  37. 200 GeV 0 RAA Important result! Several complicated (& diff) ways to get suppression? Several canceling effects? Look closer in a more natural way… PHENIX (& all others): PRL 2003 The Ubiquitous RAA… 5x fewer high pT particles than “expected” in AuAu • Common wisdom: • d-Au null effect  final state effect • so obvious that initialdAu = AuAu? • look at other hard probes from same initial processes, but withno final state effects… • Common wisdom II: • final state effect is energy loss incolor-charge-dense(not necc. deconfined) medium •  = 15 GeV/fm3 @  = 0.2 fm • ~ consistent w/ BJ and hydro… mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  38. If we are looking at energy loss… …why quantify downward shift of spectrum (as in RAA)? It seems more natural to quantify leftward shift. [Tannenbaum/Mioduzewski] • NB: ignores • Cronin (see jets() coming up…) • mods in FF (logical to look at shift of partons not their fragments) PHENIX PRL 2003 mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  39. …then let’s look at energy loss Empirical energy loss Tannenbaum/Mioduzewski mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  40. Initial pathlength dependence seems to work • Gyulassy, Vitev, Wang: • 1D expansion, simple geometric scaling • Well reproduced by experimental data. PHENIX prelim Au+Au √sNN=200 GeV mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  41.  (deg) Vary pathlength another way… qualitatively OK, now see about consistency… PHENIX prelim Au+Au √sNN=200 GeV PHENIX B. Cole, HardProbes 04 mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  42. Quantitative consistency required to claim “jet tomography” • Next level of precision needed to clarify underlying quenching mechanism • also -tagging, charm/dead-cone, q/g jet selection, correlated quenching signal versus length • (Role of dynamics in differential analysis may be significant) • cannot just put by-hand some energy loss & find consistency w/BJ No universal loss versus density path? PHENIX preliminary Overlap integral: 1D expansion pT > 3 GeV/c part(x,y) vs centrality 50-60% 10-20% PHENIX B. Cole, HardProbes 04 mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  43. HINT of charm suppression?? Too early to tell (May05) Converter method PHENIX Preliminary Nuclear modification factor Cocktail subtraction method pT (GeV/c) RAA (2.5<pT<5.0 GeV/c) mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  44. Backup mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  45. Parton Number Scaling of Elliptic Flow In the recombination regime, meson and baryon v2 can be obtained from the parton v2 (using xi = 1/n): Neglecting quadratic and cubic terms, a simple scaling law holds: Originally poposed by S. Voloshin mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  46. Suppression vs Collision Energy mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  47. NO suppression in d+Au! PHENIX BRAHMS STAR Phobos mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  48. Hadron dependence of high-pt suppression Mueller & Fries [Mueller TBS05] • R+F model describes different RAA behavior of protons and pions • Jet-quenching becomes universal in the fragmentation region mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  49. Centrality dependence of open charm in Au+Au central Compare to (PYTHIA) an event generator tuned for pp collisions… no large suppression- unlike light quarks! peripheral Comparison to pp should be available this week. Spectra of electrons from c e + anything photonic sources are subtracted mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

  50. Flowing Charm? [F. Laue TBS05] nucl-ex/0502009 inclusive e+e- v2 charmed e+e- v2 • charmed electron v2 > 0 • rule out an extreme case, charm does not interact with QGP and fragment in vacuum into D meson • get charm quark v2 with quark coalescence assumption If charm quarks also flow, charm quarks are thermalized and / or suppressed (interact with matter) similarly to the light quarks. STAR SQM04 mike lisa - Cracow School of Theoretical Physics, XLV - Zakopane Poland

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