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What is the universe made of? & What holds it together?

Some Like it REALLY Hot! Studying Matter Under Extreme Conditions Mark D. Baker Chemistry Department Brookhaven National Laboratory. What is the universe made of? & What holds it together?. What is the universe made of?. Placeholder. What holds it together?: The Fundamental Forces.

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What is the universe made of? & What holds it together?

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  1. Some Like it REALLY Hot!Studying Matter Under Extreme Conditions Mark D. BakerChemistry DepartmentBrookhaven National Laboratory What is the universe made of?&What holds it together? Mark D. Baker

  2. What is the universe made of? Placeholder Mark D. Baker

  3. What holds it together?:The Fundamental Forces Mark D. Baker

  4. Let’s smash some atoms! - + - neutron u d proton u d u d u d u d u d u u u u u u pion (p+) Mark D. Baker

  5. If you can’t smash it, heat it! Pressure Plasma - + + - - - Temperature Mark D. Baker

  6. Sideways slide - How much heat? Placeholder Mark D. Baker

  7. Heat is also a window back in time Mark D. Baker

  8. Hot and Dense Laboratory MatterTry # 1: Diamond Anvil Mark D. Baker

  9. Hot and Dense Laboratory MatterTry # 2: X-pinch plasma Mark D. Baker

  10. Hot and Dense Laboratory MatterTry # 3: Free Electron Laser XFEL, Tellerhoop, Germany l ~ 0.1 nm planned (6 nm achieved) Mark D. Baker

  11. Hot and Dense Laboratory MatterTry # 4: Heavy Ion Collisions Collide Gold nuclei at 99.99% of the speed of light 2x1012 K, 5x1021 atm But: Will these fast violent collisions teach us anything? 10-23 seconds, 10-38 liters Mark D. Baker

  12. RHIC... Mark D. Baker

  13. The PHOBOS Collaboration Birger Back, Alan Wuosmaa Mark Baker, Donald Barton, Alan Carroll, Nigel George, Stephen Gushue, George Heintzelman, Burt Holzman, Robert Pak, Louis Remsberg, Peter Steinberg, Andrei Sukhanov Andrzej Budzanowski, Roman Holynski, Jerzy Michalowski, Andrzej Olszewski, Pawel Sawicki , Marek Stodulski, Adam Trzupek, Barbara Wosiek, Krzysztof Wozniak Wit Busza (Spokesperson),Patrick Decowski, Kristjan Gulbrandsen, Conor Henderson, Jay Kane , Judith Katzy, Piotr Kulinich, Johannes Muelmenstaedt, Heinz Pernegger, Corey Reed, Christof Roland, Gunther Roland, Leslie Rosenberg, Pradeep Sarin, Stephen Steadman, George Stephans, Gerrit van Nieuwenhuizen, Carla Vale, Robin Verdier, Bernard Wadsworth, Bolek Wyslouch Chia Ming Kuo, Willis Lin, Jaw-Luen Tang Joshua Hamblen , Erik Johnson, Nazim Khan, Steven Manly,Inkyu Park, Wojtek Skulski, Ray Teng, Frank Wolfs Russell Betts, Edmundo Garcia, Clive Halliwell, David Hofman, Richard Hollis, Aneta Iordanova, Wojtek Kucewicz, Don McLeod, Rachid Nouicer, Michael Reuter, Joe Sagerer Richard Bindel, Alice Mignerey ARGONNE NATIONAL LABORATORY BROOKHAVEN NATIONAL LABORATORY INSTITUTE OF NUCLEAR PHYSICS, KRAKOW MASSACHUSETTS INSTITUTE OF TECHNOLOGY NATIONAL CENTRAL UNIVERSITY, TAIWAN UNIVERSITY OF ROCHESTER UNIVERSITY OF ILLINOIS AT CHICAGO UNIVERSITY OF MARYLAND Mark D. Baker

  14. PHOBOS Apparatus 135,000 Silicon Pad channels 12 meters of Beryllium beampipe Mark D. Baker

  15. PHOBOS Silicon Detector Octagon Detector Vertex Detector Octagon Detector: 2.7 x 8.8 mm2 Vertex Detector: 0.4 x 12 mm2 Ring Counter Mark D. Baker

  16. RHIC Computing Facility PHOBOS writes ~ 1 Gigabyte of data / minute! Mark D. Baker

  17. The plan of attack • Collide gold nuclei at high energy • Collider, detectors, computers • Understand the collision dynamics • Collective motion, equilibrium • Temperature, density • Learn about the strong interaction • Quantum ChromoDynamics • Confinement Mark D. Baker

  18. -3 0 +3 -5.5 +5.5 How many produced particles? simulation Measured # of charged particles in ahead-on collision: 4100±210 @ 130 GeV 5055±250 @ 200 GeV Mark D. Baker

  19. Models in 1999 Models in 2000 Multiplicity at mid-rapidity PRL 88 (2002) 022302 Models: NPA 698, (2002) 78c,299c Mark D. Baker

  20. Data favors models with minimal entropy production Energy Dependence PRL 88 (2002) 022302 Hard Soft 90% C.L. band Mark D. Baker

  21. Implications: • The initial state is dominated by soft physics • Limited entropy production in late stages. 1 2 3 4 Colliding Nuclei Parton Cascade Hadron Gas & Freeze-out HardCollisions QGP? / Fragmentation Gentle Freeze-out Geometry/Saturation QCD Mark D. Baker

  22. Many ways to slice pz Rapidity: Generalized velocity Feynman x: scaled pz Pseudorapidity: ~y: easier to measure Away from mid-rapidity: Mark D. Baker

  23. Latest PHOBOS results Typical Systematic Errors 200 GeV 130 GeV dN/dh dN/dh dN/dh Peripheral h h h dN/dh dN/dh dN/dh Central h h h Mark D. Baker

  24. Naïve expectation (boost-invariance) Increasing E y y Fragmentation Region dN/dy’ 0 y’=y-ybeam Mark D. Baker

  25. SPS data (20 GeV RHIC coming soon) PHOBOS results in “target frame” Results : Limiting Fragmentation PHOBOS 200 0-6% PHOBOS 130 0-6% EMU-13 17 0-9.4% (different frame) Limit curve; extent grows with energy Systematic errors not shown Mark D. Baker

  26. Can we see the “Limit Curves”? UA5, Z.Phys.C33, 1 (1986) Au+Au p + p inel. Systematic errors not included Line “p” to guide the eye 1.45 x line “p” Systematic errors not shown Mark D. Baker

  27. Elliptic Flow: A collective effect dN/d(f -YR ) = N0 (1 + 2V1cos (f-YR) + 2V2cos (2(f-YR)) + ... ) midrapidity : |h| < 1.0 V2 Hydrodynamic model Hydrodynamic “Flow” Preliminary No collective motion Normalized Multiplicity Mark D. Baker

  28. Elliptic Flow Particle asymmetry midrapidity : |h| < 1.0 V2 Hydrodynamic model Preliminary Normalized Multiplicity Mark D. Baker

  29. v2 h Flow also non-boost-invariant v2: quantifies elliptical anisotropy Azimuthal shape changes as strong function of h Averaged over centrality PHOBOS Preliminary Consistent with large e suggested by saturation (and required by some hydro models) Errors are statistical only (systematic errors ~ 0.007) Mark D. Baker

  30. Plan of attack - where are we? • Collide gold nuclei at high energy • Collider, detectors, computers • Understand the collision dynamics • Collective motion, equilibrium • Temperature, density • Learn about the strong interaction • Quantum ChromoDynamics • Confinement Mark D. Baker

  31. We see the conditions at freezeout (a lower limit to the maximum Temperature) Hottest period Freezeout Expansion cooling Mark D. Baker

  32. RHIC shows rapid expansion & a high temperature Effective Temperature (GeV) STAR Preliminary CERN NA49 1.7 1012 oK Mark D. Baker

  33. Another thermometer In an equilibrium system, two parameters are sufficient to predict the “chemical” mix: (# pions) / (# protons) (# kaons) / (# pions) (# anti-protons)/(# protons) et cetera. Temperature (T) and “net amount of matter” (mB) Mark D. Baker

  34. Particle Ratios tell us about final state Braun-Munzinger et. al., Phys. Lett. B 518 (2001) 41 Statistical models consistent with particle ratio data: simple filling of phase space? Suggest thermalization at T ~ Tc, nonzero net baryon density (SPS value: mB = 270 MeV) T = 176 MeV mB = 46 MeV 65 + 65 GeV beam energy Mark D. Baker

  35. Temperature at Freezeout • Temperature in MeV units • Chemical: T = (170 ± 20) MeV • Kinetic: T = (150 ± 40) MeV • Temperature in oK (1eV = 11,600 K) • Chemical: T = (2.0 ± 0.2) 1012 oK • Kinetic: T = (1.7 ± 0.3) 1012 oK • We did reach ~ 2 trillion K! Mark D. Baker

  36. Particle ratios at 100+100 GeV! Fully reversible magnetic field Positive Charge p K+ p+ Truncated <dE/dx> [MIP] Preliminary Negative Charge p K- p- Mark D. Baker

  37. Excitation function of mB Nucl. Phy. A697: 902-912 (2002) Extrapolation of fit Mark D. Baker

  38. eBj~ 25 GeV/fm3 eBj~ 5 GeV/fm3 Lattice ec Energy Density Estimate (Bj) PRL 87 (2001) 052301 formation time: 0.2 - 1 fm Mark D. Baker

  39. If you just believe the lattice... Karsch et al. CERN SPS (s = 17 GeV) ei ~ 3-10 GeV/fm3 Ti ~ 220-290 MeV BNL RHIC (s = 200 GeV) ei ~ 5-25 GeV/fm3 Ti ~ 250-350 MeV Mark D. Baker

  40. 400 350 RHIC 300 quark gluon plasma 250 200 Temperature (MeV) SPS 150 100 AGS SIS 50 hadron gas 0.2 0.4 0.6 0.8 1 1.2 1.4 Baryonic chemical potential mB (GeV) Putting it all together LEP! • Universal curve! • RHIC: • “bulk” matter • high energy density einitial ~ 5-25 GeV/fm3 (lattice  Ti >250 MeV) • freezeout near TC • early collective expansion vt ~ 0.65 c Mark D. Baker

  41. Summary so far • We’ve learned a lot about the system • The system is behaving collectively. • We have reached 2-4 trillion degrees K. • The system is expanding rapidly. • AA may illuminate QCD “directly” • Low Nch: soft initial state effects dominate • Thermal partons? • The source is not boost invariant • dN/dh limit curve from QCD and GAu(x) Mark D. Baker

  42. PHOBOS Future I (analysis) Quantum Mechanical Source imaging (HBT) Mark D. Baker

  43. Plan of attack - where do we go? • Collide gold nuclei at high energy • Collider, detectors, computers • Understand the collision dynamics • Collective motion, equilibrium • Temperature, density • Learn about the strong interaction • Quantum ChromoDynamics • Confinement Mark D. Baker

  44. What happens before freeze-out? • Energetic particles come from quark or gluon “jets”. • They interact with the dense medium, but can’t thermalize. • Jet energy loss (“quenching”) is predicted. • Jet quenching measures the density early in the collision. pion Mark D. Baker

  45. Failure to scale! (jet quenching?) Details need to be understood before conclusions can be drawn. Mark D. Baker

  46. PHOBOS Future II Compare high Pt behavior of: pp, dA, AA (as well as soft behavior) • I. Faster!! • Upgrade DAQ from • 40 Hz to 500-700 Hz • Upgrade triggering • II. Better particle ID • Move TOF wall • +... Sukhanov R.Pak Mark D. Baker

  47. PHOBOS future III (analysis) Lower pT at pp midrapidity ISR data is inelastic Universality? Mark D. Baker

  48. Brookhaven Future (!): eRHIC • Directly probe dense strongly interacting matter. • Nonabelian QCD effects in the low x nuclear structure function... Mark D. Baker

  49. Conclusion • We’ve accomplished a lot already • Detector, physics, papers. • RHIC should illuminate QCD “directly” • dN/dh limit curve from QCD and GAu(x) • Universality of “fragmentation” • “Jet quenching” or new scaling law • Something we haven’t thought of yet... • Physics on the distant horizon • eRHIC - probing QCD in a different way. Mark D. Baker

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