Nu Xu //Nxu/tex 3/TALK/2004/08 CCAST Lawrence Berkeley National Laboratory Part I: QM 04 Highlights (experiment) Part II: Transverse Dynamics at RHIC Nu Xu CCAST, Beijing, China, 2004 1
QM 04 Highlights //Nxu/tex 3/TALK/2004/08 CCAST Part I Nu Xu CCAST, Beijing, China, 2004 2
Quark Matter Conference //Nxu/tex 3/TALK/2004/08 CCAST http: //qm 2004. lbl. gov/ Nu Xu CCAST, Beijing, China, 2004 3
ARC //Nxu/tex 3/TALK/2004/08 CCAST Blue Ring (clockwise) Yellow Ring Four Experiments: BRAHMS PHENIX PHOBOS STAR ~ 1200 physicists: high energy/nuclear Started in the Summer of 2000 ~ 200 publications (summer ‘ 04) Nu Xu CCAST, Beijing, China, 2004 4
RHIC @ Brookhaven National Laboratory //Nxu/tex 3/TALK/2004/08 CCAST PHOBOS BRAHMS PHENIX h Nu Xu STAR CCAST, Beijing, China, 2004 5
Colliding Systems //Nxu/tex 3/TALK/2004/08 CCAST 1. Run-I 2. Au+Au 2000 3. Run-II 4. 200 Ge. V Au+Au p+p 2001 5. Run-III 200 Ge. V d+Au 2002 6. Run-IV Nu Xu 19. 6 Ge. V 130 Ge. V 200 Ge. V Au+Au 2004 CCAST, Beijing, China, 2004 6
People at RHIC //Nxu/tex 3/TALK/2004/08 CCAST More than 1000 people from around the world Brazil, Canada, China, Croatia, Denmark, France, Germany, India, Israel, Japan, Korea, Norway, Poland, Russia, Sweden, UK, USA Nu Xu CCAST, Beijing, China, 2004 7
Physics Goals at RHIC //Nxu/tex 3/TALK/2004/08 CCAST Identify and study the properties of matter with partonic degrees of freedom. Penetrating probes Bulk probes - direct photons, leptons - “jets” and heavy flavor - spectra, v 1, v 2 … - partonic collectivity - fluctuations = Hydrodynamic Local jets - observed high p. T hadrons (at RHIC, p. T(min) > 3 Ge. V/c) Collectivity collectivity - collective motion of observed hadrons, not necessarily reached Flow Thermalization thermalization among them. Nu Xu CCAST, Beijing, China, 2004 8
//Nxu/tex 3/TALK/2004/08 CCAST Phase diagram of strongly interacting matter CERN-SPS, RHIC, LHC: high temperature, low baryon density AGS, GSI (SIS 200): Nu Xu moderate temperature, high baryon density CCAST, Beijing, China, 2004 9
QCD on Lattice //Nxu/tex 3/TALK/2004/08 CCAST 1) Large increase in a fast cross cover ! 2) Does not reach ideal, non-interaction S. Boltzmann limit ! many body interactions Collective modes Quasi-particles are necessary Lattice calculations predict TC ~ 170 Me. V 3) TC ~ 170 Me. V robust! Z. Fodor et al, JHEP 0203: 014(02) Z. Fodor et al, hep-lat/0204001 C. R. Allton et al, hep-lat/0204010 F. Karsch, Nucl. Phys. A 698, 199 c(02). Nu Xu CCAST, Beijing, China, 2004 10
Study of Nuclear Collisions Like… //Nxu/tex 3/TALK/2004/08 CCAST P. C. Sereno et al. Science, Nov. 13, 1298(1998). (Spinosaurid) High p. T QCD probes Bulk Properties Nu Xu CCAST, Beijing, China, 2004 11
Au + Au Collisions at RHIC //Nxu/tex 3/TALK/2004/08 CCAST Central Event STAR Nu Xu (real-time Level 3) CCAST, Beijing, China, 2004 12
Collision Geometry, Flow //Nxu/tex 3/TALK/2004/08 CCAST z Au + Au s. NN = 200 Ge. V x Non-central Collisions Number of participants: number of incoming nucleons in the overlap region Number of binary collisions: number of inelastic nucleon-nucleon collisions Charged particle multiplicity Reaction plane: x-z plane Nu Xu collision centrality CCAST, Beijing, China, 2004 13
Global: Charge hadron density //Nxu/tex 3/TALK/2004/08 CCAST 19. 6 Ge. V 130 Ge. V 200 Ge. V PHOBOS Collaboration Charged hadron pseudo-rapidity 1) High number of Nch indicates initial high density; 2) Mid-y, Nch Npart nuclear collisions are not incoherent; 3) Saturation model works Important for high density and thermalization. PRL 85, 3100 (00); 91, 052303 (03); 88, 22302 (02), 91, 052303 (03) Nu Xu CCAST, Beijing, China, 2004 14
Particle production at RHIC //Nxu/tex 3/TALK/2004/08 CCAST 0 1 2 3 4 5 6 7 8 9 10 11 12 Ge. V/c Soft (hydro) p. QCD Bulk production Collective effects New form of matter Nu Xu Unclear region New observations CCAST, Beijing, China, 2004 Large Q 2 results Medium modification of hard probes - parton energy loss 15
//Nxu/tex 3/TALK/2004/08 CCAST High/Intermediate p. T 1) Expect QCD calculations can be used as guidance 2) New tool at high energy nuclear collisions Nu Xu CCAST, Beijing, China, 2004 16
Energy Loss in A+A Collisions //Nxu/tex 3/TALK/2004/08 CCAST leading particle suppressed back-to-back jets disappear p+p Au + Au Nuclear Modification Factor: Nu Xu CCAST, Beijing, China, 2004 17
Jet Quenching //Nxu/tex 3/TALK/2004/08 CCAST Hadron suppression at intermediate p. T, caused by energy loss of energetic objects, - ‘Jet quenching’! Nu Xu CCAST, Beijing, China, 2004 18
Jets Observation at RHIC //Nxu/tex 3/TALK/2004/08 CCAST p+p collisions at RHIC Jet like events observed Nu Xu CCAST, Beijing, China, 2004 Au+Au collisions at RHIC Jets? 19
Suppression and correlation //Nxu/tex 3/TALK/2004/08 CCAST Hadron suppression and disappearance of back-to-back ‘jet’ are correlated! Nu Xu CCAST, Beijing, China, 2004 20
Di-jet tomography: Predictions //Nxu/tex 3/TALK/2004/08 CCAST Out-of-plane In-plane d. E/dx path length L! X. N. Wang Nu Xu CCAST, Beijing, China, 2004 21
Di-hardron tomography //Nxu/tex 3/TALK/2004/08 CCAST STAR Preliminary STAR preliminary A. Tang QM 04 20 -60% p. Ttrig=4. 0 -6. 0 Ge. V/c, | |<1. 0, 2. 0<p. Tassoc<p. Ttrig - Back-to-back suppression depends on the reaction plane orientation: i. e. energy loss dependence on the path length -Powerful tool to study hadronization process in heavy ion collisions Nu Xu CCAST, Beijing, China, 2004 22
Energy loss and equilibrium //Nxu/tex 3/TALK/2004/08 CCAST Leading hadrons Medium In Au +Au collision at RHIC: - Suppression at the intermediate p. T region - energy loss cause by the final state interactions - The energy loss leads to progressive equilibrium in Au+Au collisions STAR: nucl-ex/0404010 Nu Xu CCAST, Beijing, China, 2004 23
Direct : a colorless probe //Nxu/tex 3/TALK/2004/08 CCAST PHENIX Preliminary (Pb. Gl / Pb. Sc Combined) 1 + ( p. QCD direct x Ncoll) / phenix backgrd Vogelsang NLO 1 + ( p. QCD direct x Ncoll) / ( phenix pp backgrd x Ncoll) Transverse momentum p. T (Ge. V/c) PHENIX: Direct photons are described by a curve that includes the measured suppressed 0 production in Au+Au collisions. (Au+Au at 200 Ge. V: 0 -10%) Nu Xu CCAST, Beijing, China, 2004 24
//Nxu/tex 3/TALK/2004/08 CCAST RAA for 0 in Central Collisions D. d’Enterria QM 04 nucl-ex/0403055 SPS Energies: A. L. S. Angelis, PL B 185, 213 (87) WA 98, EPJ C 23, 225 (2002) RHIC Energies: PHENIX, PRL 88 022301 (02) PRL 91, 072303 (03) p+p collision results changed Finite energy loss in central heavy ion collisions at SPS energies! Nu Xu CCAST, Beijing, China, 2004 25
//Nxu/tex 3/TALK/2004/08 CCAST Summary: High/Intermediate p. T 1) From run I - III, particle spectra were measured up to p. T~10 -12 Ge. V/c; 2) Energy loss effect observed at intermediate region in central Au+Au collisions at 200 Ge. V; 3) Back-to-back ‘jets’ disappears; 4) The energy loss depends on the path length - new! Future: • • Nu Xu Cronin effect - energy, hadron type dependence Hadronization process in p+p and Au+Au collisions Origin of v 2 at intermediate p. T region (2 -6 Ge. V/c) … CCAST, Beijing, China, 2004 26
Open Charm Production //Nxu/tex 3/TALK/2004/08 CCAST 1) Production through gluon fusing - sensitive to the initial condition for heavy ion collisions 2) Interacting with medium - sensitive to medium properties 3) Heavy intrinsic mass - a test the predictive power of QCD calculation Nu Xu CCAST, Beijing, China, 2004 27
QCD Energy Scale //Nxu/tex 3/TALK/2004/08 CCAST 1/x m. C s-quark mass ~ 0. 2 Ge. V, similar to values of TC critical temperature QCD scale parameter TCH chemical freeze-out temperature = 4 f chiral breaking scale c-quark mass ~ 1. 2 - 1. 5 Ge. V >> QCD -- p. QCD production - parton density at small-x -- QCD interaction - medium properties Rcc ~ 1/m. C => color screening J/ => deconfinement and thermalization u-, d-, s-quarks: light-flavors || c-, b-quarks: heavy-flavors Nu Xu CCAST, Beijing, China, 2004 28
Electron spectra //Nxu/tex 3/TALK/2004/08 CCAST STAR Preliminary An increasing excess found at higher p. T region, p. T > 1. 0 Ge. V/c, Expected contribution of semi-leptonic decays from heavy flavor hadrons Nu Xu CCAST, Beijing, China, 2004 29
Consistent in D measurements //Nxu/tex 3/TALK/2004/08 CCAST STAR: nucl-ex/0404029 Directly reconstructed D mesons STAR Preliminary Electrons from D decay D and electron spectra are consistent! Nu Xu CCAST, Beijing, China, 2004 30
Open Charm spectra //Nxu/tex 3/TALK/2004/08 CCAST STAR: nucl-ex/0406 An increasing excess found at higher p. T region, p. T > 1. 0 Ge. V/c, Expected contribution of semi-leptonic decays from heavy flavor hadrons p. QCD distributions are steeper and total cross sections are lower CGC: D. Kharzeev and K. Tuchin, Nu Xu CCAST, Beijing, China, 2004 NPA 735, 248(04). 31
Charm production cross-section //Nxu/tex 3/TALK/2004/08 CCAST 1) NLO p. QCD calculations under-predict the ccbar production cross section at RHIC STAR Preliminary 2) Power law for ccbar production cross section from SPS to RHIC: 3) n~2 (n~0. 5 for charged hadrons) 3) Large uncertainties in total cross section due to rapidity width, model dependent(? ). Nu Xu CCAST, Beijing, China, 2004 32
Some SPS results //Nxu/tex 3/TALK/2004/08 CCAST Nu Xu CCAST, Beijing, China, 2004 33
NA 49 Experiment http: //na 49 info. cern. ch/ //Nxu/tex 3/TALK/2004/08 CCAST Pb+Pb collision at 158 A Ge. V Nu Xu CCAST, Beijing, China, 2004 34
Rapidity spectra //Nxu/tex 3/TALK/2004/08 CCAST also: , Extrapolation 4π yields (open dots from reflection at ycm= 0) Nu Xu CCAST, Beijing, China, 2004 35
Statistical model at at 40 A, 80 A Ge. V //Nxu/tex 3/TALK/2004/08 CCAST At lower energies B increases, while T decreases slightly Nu Xu CCAST, Beijing, China, 2004 36
Particle yields – statistical model //Nxu/tex 3/TALK/2004/08 CCAST (fits by F. Becattini et al, PRC 69(2004)024905) • hadron species populated according to phase space probabilities (max. entropy) (Fermi, Hagedorn) • strangeness sector not fully saturated (Rafelski) • statistical model successful, T, B, S, V • larger value of S in A+A due to relaxation of local strangeness conservation Nu Xu CCAST, Beijing, China, 2004 37
Ratio of strange hadrons to pions //Nxu/tex 3/TALK/2004/08 CCAST ed mix partonic Strangeness to pion ratio peaks sharply at the SPS hadro nic mixed partonic deconfinement? hadronic Nu Xu CCAST, Beijing, China, 2004 38
Mid-rapidity transverse mass spectra //Nxu/tex 3/TALK/2004/08 CCAST 158 A Ge. V well described by fireball model assuming common temperature and flow “blast wave”: (Schnedermann, Sollfrank, Heinz : PRC 48 (1993) 2462) Nu Xu CCAST, Beijing, China, 2004 39
Part I: summary //Nxu/tex 3/TALK/2004/08 CCAST 1. 2. 3. 4. 5. 6. Nu Xu Topics are not covered: Color Glass Condensation: small-x cold QCD physics Peripheral collisions at RHIC HBT issues at RHIC Astrophysics and heavy ion collisions New theoretical development CCAST, Beijing, China, 2004 40
Transverse Dynamics at RHIC //Nxu/tex 3/TALK/2004/08 CCAST Part II Nu Xu CCAST, Beijing, China, 2004 41
Pressure, Flow, … //Nxu/tex 3/TALK/2004/08 CCAST tds = d. U + pd. V s– entropy; p – pressure; U – energy; V – volume t = k. BT, thermal energy per dof In high-energy nuclear collisions, interaction among constituents and density distribution will lead to: pressure gradient collective flow number of degrees of freedom (dof) Equation of State (EOS) No thermalization is needed – pressure gradient only depends on the density gradient and interactions. Space-time-momentum correlations! Nu Xu CCAST, Beijing, China, 2004 42
Transverse flow observables //Nxu/tex 3/TALK/2004/08 CCAST As a function of particle mass: • • • Directed flow (v 1) – early Elliptic flow (v 2) – early Radial flow – integrated over whole evolution Note on collectivity: 1) Effect of collectivity is accumulative – final effect is the sum of all processes. 2) Thermalization is not needed to develop collectivity pressure gradient depends on density gradient and interactions. Nu Xu CCAST, Beijing, China, 2004 43
Hadron spectra from RHIC p+p and Au+Au collisions at 200 Ge. V //Nxu/tex 3/TALK/2004/08 CCAST Nu Xu CCAST, Beijing, China, 2004 44
Hadron production & chemical freeze-out //Nxu/tex 3/TALK/2004/08 CCAST 1) Chemical fit well to all hadron ratios at RHIC: Tch = 160 ± 10 Me. V B = 25 ± 5 Me. V S = 1 ± 0. 05 Necessary for QGP! 2) The temperature parameter Tch is close to the critical temperature TC predicted by LGT calculations chemical equilibrium at the phase boundary 3) Since 1999, many work in this direction Review: P. Braun-Munzinger et al. nucl-th/0304013 Nu Xu CCAST, Beijing, China, 2004 45
Compare with hydrodynamic model //Nxu/tex 3/TALK/2004/08 CCAST This model results fit to pion, Kaon, and proton spectra well, but over predicted the values of <p. T> for multi-strange hadrons Nu Xu CCAST, Beijing, China, 2004 46
Hydro model: for , , p spectra //Nxu/tex 3/TALK/2004/08 CCAST Nu Xu CCAST, Beijing, China, 2004 47
Thermal model fit //Nxu/tex 3/TALK/2004/08 CCAST Source is assumed to be: – Local thermal equilibrated – Boosted radically boosted E. Schnedermann, J. Sollfrank, and U. Heinz, Phys. Rev. C 48, 2462(1993) random Nu Xu CCAST, Beijing, China, 2004 48
Early freeze-out //Nxu/tex 3/TALK/2004/08 CCAST Central Au+Au collisions at RHIC 1) Multi-strange hadrons seem to freeze out earlier than others sensitive probe for early dynamics 2) Charm-hadrons should be better. A possible complication is the p. QCD hard spectrum. 3) J/ coalescence/melting: a tool for early dynamics CGC, deconfinement, and thermal equilibrium Chemical Freeze-out: inelastic interactions stop Kinetic Freeze-out: elastic interactions stop Nu Xu CCAST, Beijing, China, 2004 PHENIX: Phys. Rev. C 69 034909 (04). STAR: Phys. Rev. Lett. 92, 112301(04); Phys. Rev. Lett. 92, 182301(04). A. Andronic et al. , NPA 715, 529(03). P. Kolb et al. , Phys. Rev. C 67 044903(03) 49
Blast wave fits: Tfo vs. < T > //Nxu/tex 3/TALK/2004/08 CCAST 200 Ge. V Au + Au collisions 1) p, K, and p change smoothly from peripheral to central collisions. 2) At the most central collisions, < T> reaches 0. 6 c. 3) Multi-strange particles , are found at higher T and lower < T> Sensitive to early partonic stage! How about v 2? STAR: NPA 715, 458 c(03); PRL 92, 112301(04); 92, 182301(04). Nu Xu CCAST, Beijing, China, 2004 50
Equation of State //Nxu/tex 3/TALK/2004/08 CCAST With given degrees of freedom, the EOS - the system response to the changes of thermal condition - is fixed by its p and T( ). Nu Xu Energy density Ge. V/fm 3 Equation of state: - EOS I : relativistic ideal gas: p = /3 - EOS H: resonance gas: p ~ /6 - EOS Q: Maxwell construction: Tcrit= 165 Me. V, B 1/4 = 0. 23 Ge. V lat=1. 15 Ge. V/fm 3 P. Kolb et al. , Phys. Rev. C 62, 054909 (2000). CCAST, Beijing, China, 2004 51
Anisotropy parameter v 2 //Nxu/tex 3/TALK/2004/08 CCAST coordinate-space-anisotropy momentum-space-anisotropy y py x px Initial/final conditions, Eo. S, degrees of freedom Nu Xu CCAST, Beijing, China, 2004 52
v 2 at Low p. T //Nxu/tex 3/TALK/2004/08 CCAST P. Huovinen, private communications, 2004 - At low p. T, hydrodynamic model fits well for minimum bias events indicating early thermalization in Au+Au collisions at RHIC! - More theory work needed to understand details: such as centrality dependence of v 2; consistency between spectra and v 2 … Nu Xu CCAST, Beijing, China, 2004 53
Partonic collectivity at RHIC //Nxu/tex 3/TALK/2004/08 CCAST PHENIX: PRL 91, 182301(03) STAR: PRL 92, 052302(04) v 2, the spectra of multistrange hadrons, and the scaling of the number of constituent quarks Partonic collectivity has been attained at RHIC! Deconfinement, model dependently, has been attained at RHIC! Next question is thermalization of light flavors at RHIC: - v 2 of charm hadrons - J/ yield, distributions Nu Xu CCAST, Beijing, China, 2004 54
Nuclear modification factor //Nxu/tex 3/TALK/2004/08 CCAST 1) Baryon vs. meson effect! 2) Hadronization via coalescence - (K 0, ): PRL 92, 052303(04); NPA 715, 466 c(03); - R. Fries et al, PRC 68, 044902(03) Nu Xu 3) Deconfinement at RHIC CCAST, Beijing, China, 2004 55
Freeze-out systematics //Nxu/tex 3/TALK/2004/08 CCAST The additional increase in T is likely due to partonic pressure at RHIC. 1) Smaller baryon chemical potential B = 25 Me. V with Tch = 160 Me. V 2) Stronger transverse flow, T= 0. 6(c) Nu Xu CCAST, Beijing, China, 2004 56
//Nxu/tex 3/TALK/2004/08 CCAST STAR 200 Ge. V v 2 Anti-proton fit well by the hydrodynamic model with initial velocity kick ( = 0. 02 fm-1), but pions fail! Much more theory work ahead P. Kolb and R. Rapp, Phy. Rev. C 67, 044903(2002) Nu Xu CCAST, Beijing, China, 2004 57
Partonic collectivity at RHIC //Nxu/tex 3/TALK/2004/08 CCAST 1) Copiously produced hadrons freeze-out: Tfo = 100 Me. V, T = 0. 6 (c) > T(SPS) 2)* Multi-strange hadrons freeze-out: Tfo = 170 Me. V (~ Tch), T = 0. 4 (c) 3)** Multi-strange v 2: Multi-strange hadrons and flow! 4)*** Constituent quark scaling: Seems to work for v 2 and RAA (RCP) Partonic (u, d, s) collectivity at RHIC Nu Xu CCAST, Beijing, China, 2004 58
Summary //Nxu/tex 3/TALK/2004/08 CCAST (1) Flavor equilibration - necessary for QGP (2)(2) Jet energy loss - QCD at work (3)(3) Collectivity - pressure gradient ∂PQCD Deconfinement and Partonic collectivity First time ever, re-produced partonic matter in the laboratory since big bang. Nu Xu CCAST, Beijing, China, 2004 59
//Nxu/tex 3/TALK/2004/08 CCAST Phase diagram of strongly Discover QGP and more! interacting matter LHC RHIC GSI 200 CERN-SPS, RHIC, LHC: high temperature, low baryon density AGS, GSI (SIS 200): Nu Xu moderate temperature, high baryon density CCAST, Beijing, China, 2004 60
Some Future reading: //Nxu/tex 3/TALK/2004/08 CCAST - http: //qm 2004. lbl. gov/ - Quark Matter conference proceedings 2002 Nucl. Phys. A 715, 1 c(2003). - Quark Matter conference proceedings 2001 Nucl. Phys. A 698, 1 c(2002). - “Introduction to High Energy Heavy Ion Collisions’’ - By C. Y. Wong (Oak Ridge), . 1995. Singapore, Singapore: World Scientific (1994) 516 p. - “Introduction to Relativistic Heavy Ion Collisions’’ - By L. P. Csernai (Bergen U. ), . 1994. Chichester, UK: Wiley (1994) 310 p. - Recent discussions on the QGP discovery http: //www. bnl. gov/riken/May 14 -152004 workshop. htm Nu Xu CCAST, Beijing, China, 2004 61
//Nxu/tex 3/TALK/2004/08 CCAST Nu Xu CCAST, Beijing, China, 2004 62
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