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Results and Perspectives

Results and Perspectives. G á bor I. Veres E ö tv ö s Lor á nd University, Budapest and Massachusetts Institute of Technology, Cambridge for the collaboration RHIC & AGS Annual Users’ Meeting June 23, 2005. PHOBOS Workshop talks:

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Results and Perspectives

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  1. Results and Perspectives Gábor I. Veres Eötvös Loránd University, Budapest and Massachusetts Institute of Technology, Cambridge for the collaboration RHIC & AGS Annual Users’ Meeting June 23, 2005 PHOBOS Workshop talks: George Stephans - Femtoscopy (Tue 6/21) Zhengwei Chai - Multiplicity Fluctuations (Tue 6/21) PHOBOS Posters by: Abigail Bickley, Richard Hollis, Carla Vale

  2. CuCu@200 CuCu@62.4 Another year of spectacular achievement for RHIC & C-AD THANKS!!! • Run 5 is the most diverse run so far: • 9 weeks of Cu+Cu at 200 GeV (6 nb-1) • 2 weeks of Cu+Cu 62.4 GeV (0.25 nb-1) • 2 days of Cu+Cu 22.5 GeV • few hours of p+p at 410 and 200 GeV Gábor I. Veres

  3. The Collaboration (June 2005) Burak Alver, Birger Back,Mark Baker, Maarten Ballintijn, Donald Barton, Russell Betts, Richard Bindel, Wit Busza (Spokesperson), Zhengwei Chai, Vasundhara Chetluru, Edmundo García, Tomasz Gburek, Kristjan Gulbrandsen, Clive Halliwell, Joshua Hamblen, Ian Harnarine, Conor Henderson, David Hofman, Richard Hollis, Roman Hołyński, Burt Holzman, Aneta Iordanova, Jay Kane, Piotr Kulinich, Chia Ming Kuo, Wei Li, Willis Lin, Steven Manly, Alice Mignerey, Gerrit van Nieuwenhuizen, Rachid Nouicer, Andrzej Olszewski, Robert Pak, Corey Reed, Eric Richardson, Christof Roland, Gunther Roland, Joe Sagerer, Iouri Sedykh, Chadd Smith, Maciej Stankiewicz, Peter Steinberg, George Stephans, Andrei Sukhanov, Artur Szostak, Marguerite Belt Tonjes, Adam Trzupek, Sergei Vaurynovich, Robin Verdier, Gábor Veres, Peter Walters, Edward Wenger, Donald Willhelm, Frank Wolfs, Barbara Wosiek, Krzysztof Woźniak, Shaun Wyngaardt, Bolek Wysłouch ARGONNE NATIONAL LABORATORY BROOKHAVEN NATIONAL LABORATORY INSTITUTE OF NUCLEAR PHYSICS PAN, KRAKOW MASSACHUSETTS INSTITUTE OF TECHNOLOGY NATIONAL CENTRAL UNIVERSITY, TAIWAN UNIVERSITY OF ILLINOIS AT CHICAGO UNIVERSITY OF MARYLAND UNIVERSITY OF ROCHESTER Gábor I. Veres

  4. Outline • What did we learn in the five years of PHOBOS history? • Results since the last Users’ Meeting • Plans and perspectives of PHOBOS Gábor I. Veres

  5. system GeV 5 years of PHOBOS… Data we took in various runs: Gábor I. Veres

  6. system GeV PHOBOS: number of events on tape… [in millions] Gábor I. Veres

  7. Evolution of the detector – Pre-run 1: AuAu Gábor I. Veres

  8. Run 1: Au+Au Gábor I. Veres

  9. Run 2: Au+Au and p+p

  10. Run 3: d+Au and p+p Gábor I. Veres

  11. Run 4 and 5: Au+Au, Cu+Cu Gábor I. Veres

  12. Run 4 and 5: p+p Gábor I. Veres

  13. Run 6… Gábor I. Veres

  14. Run 5 All-inclusive count, Including tests Run 4 Run 3 Run 2 Data rate and number of events taken Continuous DAQ upgrades! Over a billion events taken Gábor I. Veres

  15. Slave Slave Master Slave Slave Internet PROOF User The PHOBOS computing architecture … to cope with hundreds of millions of events • CatWeb –data management (650k files, 400 TByte) • Easy www interface to stage HPSSRCF • API for access to functionality from ROOT/PhAT • Distributed disks • 100 TByte, fast access • ALL physics data is stored on disks! • AnT – Analysis Tree DST format • ROOT Tree based, fast access to subsets of data • Well structured, links hits to tracks etc. • PROOF – Parallel ROOT Facility • Parallel interactive analysis, over x100 speed-up! • Co-exist with regular batch usage Gábor I. Veres

  16. PHOBOS physics publications 24 papers, including 12 in Phys. Rev. Letters The PHOBOS Perspective on Discoveries at RHICScaling of Charged Particle Production in d+Au Collisions at sqrt(s_NN)=200 GeVCharged antiparticle to particle ratios near midrapidity in p+p collisions at sqrt(s_NN) = 200 GeVTransverse momentum and rapidity dependence of HBT correlations in Au+Au collisions at sqrt(s_NN) = 62.4 and 200 GeVCentrality and pseudorapidity dependence of elliptic flow for charged hadrons in Au+Au collisions at sqrt(s_NN)= 200 GeVEnergy dependence of elliptic flow over a large pseudorapidity range in Au+Au collisions at RHICPseudorapidity dependence of charged hadron transverse momentum spectra in d+Au collisions at sqrt(s_NN)=200 GeVCollision Geometry Scaling of Au+Au pseudorapidity density from sqrt(s_NN) = 19.6 to 200 GeVCentrality dependence of charged hadron transverse momentum spectra in Au+Au collisions from sqrt(s_NN) = 62.4 to 200 GeVParticle production at very low transverse momenta in Au+Au collisions at sqrt(s_NN)=200 GeVPseudorapidity Distribution of Charged Particles in d+Au collisions at sqrt(s_NN)=200 GeVCentrality dependence of charged antiparticle to particle ratios near mid-rapidity in d+Au collisions at sqrt(s_NN)=200 GeVCentrality Dependence of the Charged Hadron Transverse Momentum Spectra in d+Au Collisions at  sqrt(sNN)=200 GeVCharged hadron transverse momentum distributions in Au+Au collisions at sqrt(s_NN) = 200 GeVComparison of the Total Charged-Particle Multiplicity in High-Energy Heavy Ion Collisions with e+e- and pp/pbar-p DataSignificance of the fragmentation region in ultrarelativistic heavy ion collisionsRatios of charged antiparticles to particles near mid-rapidity in Au+Au collisions at sqrt(sNN)=200 GeVPseudorapidity and centrality dependence of the collective flow of charged particles in Au+Au collisions at sqrt(sNN)=130 GeV Centrality Dependence of the Charged Particle Multiplicity near Mid-Rapidity in  Au+Au Collisions at sqrt(sNN)=130 and 200 GeV Energy dependence of particle multiplicities near mid-rapidity in central Au+Au collisions Centrality Dependence of Charged Particle Multiplicity at Midrapidity in Au+Au Collisions at sqrt(sNN)=130 GeV Charged-particle pseudorapidity density distributions from Au+Au collisions at sqrt(sNN)=130 GeV Ratios of charged particles to antiparticles near mid-rapidity in Au+Au collisions at sqrt(sNN)=130 GeV Charged particle multiplicity near mid-rapidity in central Au+Au collisions at sqrt(s) = 56 and 130 AGeV Gábor I. Veres

  17. “White Paper”: summary of PHOBOS results nucl-ex/0410022, Nucl. Phys. A 757, 28 • We have created a state of matter at RHIC with high energy-density, that is nearly net-baryon free and interacting very strongly. • Transition to this high-energy state of matter does not create abrupt changes in observables at RHIC energies. • The data exhibit “simple” scaling behavior and factorization.→ suggests strong global constraints and illustrates the importance of the collision geometry in the initial state and the early evolution of the colliding system. Gábor I. Veres

  18. p+p A+A High energy density & nearly baryon-free matter Energy Density Estimate: eRHIC > 3 GeV/fm3 • Energy density ~6x that of nucleons (20x that of nuclei) Particle Ratios: Approaching Unity (Our new result is p+p@200GeV) • mB at full RHIC energy is a factor ~10 smaller than at SPS. Gábor I. Veres

  19. d+Au 0-20% 1.5 RAA, RdAu 1.0 0.5 PHOBOS PRC 70, 061901 Au+Au 0-6% 0 0 d+Au Strongly interacting matter… …flow PHOBOS nucl-ex/0407012 • Elliptic flow reaches hydro limit • Suppressed high-pT production • No enhanced low-pT production hydro 200 GeV Au+Au, 0-50% …high-pT …low-pT PHOBOS PRC 70, 051901(R) PHOBOS PRL 91, 072302 200 GeV Au+Au Gábor I. Veres

  20. 200 GeV Au+Au Gábor I. Veres

  21. Estimated extrapolation to 5% Phobos 15% data Recent theoretical interest at low pT J. G. Cramer et al., Phys. Rev. Lett. 94, 102302 (2005) (George Stephans’ talk) and PHOBOS comment: nucl-ex/0506008 data: ( Au+Au 15% central Gábor I. Veres

  22. v2 Track-based 200 GeV Hit-based 200 GeV Hit-based 130 GeV PHOBOS SPS PHOBOS nucl-ex/0407012 AGS PHOBOS Nucl.Phys.A 757,28 Npart Transition is gradual, not abrupt… …vs. energy …vs. centrality 62.4 GeV 200 GeV Au+Au PHOBOS PRL 94, 082304 Gábor I. Veres

  23. d+Au Extended longitudinal scaling… …in dN/dh (p+p, d+Au, Au+Au): PHOBOS nucl-ex/0409021 …in v2 (elliptic flow): PHOBOS PRL 94, 122303 Gábor I. Veres

  24. Universality of Nch e+e-, p+p, A+A data produces the same Nch Npart scaling: Au+Au, d+Au d+Au p+p Au+Au PHOBOS nucl-ex/0301017 & Nucl. Phys. A 757, 28 Gábor I. Veres

  25. 200/19.6 GeV R(200/X) 200/130 GeV <pT>= 0.25 1.25 2.50 3.38 3.88 GeV/c 200/62.4 GeV <Npart> Factorization of geometry and energy Ratio of dN/dh|h=0 at different energies: Also differentially, at various pT values: Gábor I. Veres

  26. PHOBOS preliminary Our most recent results: dN/dh in Au+Au at 62.4 GeV • most recent Au+Au run • B field off • 2 centrality methods: • scint. paddles at 3.2<h<4.5 • octagon |h|<3 • 3 different dN/dh methods: • analog, digital, ‘tracklets’ Gábor I. Veres

  27. PHOBOS preliminary The most central data compared to other energies Gábor I. Veres

  28. p+p(p) A+A Our new 64.2 GeV point fits into the trend • Mid-rapidity yields in • ~6% most central events • Logarithmic rise PHOBOS preliminary Gábor I. Veres

  29. PHOBOS preliminary Factorization of beam energy and collision geometry is also valid at 62.4 GeV • at higher energies, hard collisions • should be more dominant • Ncoll/Npart increases with centrality • still, energy-independent • centrality evolution Factorization of energy and collision geometry Gábor I. Veres

  30. PHOBOS preliminary Extended longitudinal scaling of charged hadrons (Also in d+Au and in v2) Gábor I. Veres

  31. PHOBOS preliminary 90% C.L. syst. errors RPC is precisely energy independent Npart Ratio of 0-6% and 35-40% centrality bins, each normalized by Npart Gábor I. Veres

  32. Total charged particle yields: Npart scaling Error bands from the extrapolation to high h • Integrated over the full h range • Nch is linearly increasing with Npart • “wounded nucleon scaling” • Scaled multiplicity is higher than in p+p PHOBOS preliminary Gábor I. Veres

  33. Plans, Perspectives Data taking for PHOBOS has ended, but… …lots of data on tape, still to be analyzed in the next years: • Charged hadron spectra in Cu+Cu, p+Au, n+Au collisions • Identified spectra and particle/antiparticle ratios (Cu+Cu, Au+Au) • Particle production at very low pT (G. Stephans’ talk) • Measurement of the Φ meson • Multiplicity analysis using ‘tracklets’ and digital/analog method • Event-by-event multiplicity fluctuations (Z. Chai’s talk) • Two-particle correlations in d+Au collisions • Elliptic and directed flow measurements • Rare event searches • etc… More news to come! Gábor I. Veres

  34. Summary • Another great year for RHIC (& PHOBOS) • “White Paper” reviews from the four experiments • Spectacular and diverse run with many different collisions, and upgraded DAQ and computing • Luminosities even exceeding the goals • Multiplicity measurement at 62.4 GeV • Fits into the known evolution with energy • Various scaling features observed/confirmed • Data are simpler than the models! • Lot of data is still preliminary/in the works: • Much more results to come in the (near) future! …see you in Budapest! Gábor I. Veres

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  36. Gábor I. Veres

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