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The Universe's Origins in a Beer Pool

This article discusses a new discovery that suggests the universe may have originated from a pool of beer. It also explores the concept of matter existing in a "superfluid" state across different forms. The article provides information on the search for the Quark Gluon Plasma and the QCD Phase Diagram of Hadronic Matter. Additionally, it discusses the experiments conducted at the Relativistic Heavy-Ion Collider (RHIC) and the findings from the RHIC experiments.

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The Universe's Origins in a Beer Pool

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  1. http://science.slashdot.org/ #12288165: This finally proves what I have been trying to explain for years.. the universe was born from a pool of beer! #12288394: Matter can be in a "superfluid" state when in solid, liquid, gas, and plasma form (this is a fairly new discovery).The term "superfluid" has more to do with whether various properties obtain than being an actual fluid.

  2. Where are we in the Search for the Quark Gluon Plasma?Experimental Evaluation of the First 4 Years at RHIC Thomas Ullrich, BNL XXV Physics in Collision 2005 Prague, July 6-9, 2005

  3. G. Schierholz et al., Confinement 2003 Critical energy density: Action density in 3 quark system in full QCD H. Ichie et al., hep-lat/0212036 Lattice QCD at Finite Temperature • Coincident transitions: deconfinement and chiral symmetry restoration • Recently extended to mB> 0, order still unclear (2nd, crossover ?) TC ~ 175 MeV  eC ~ 1 GeV/fm3

  4. QCD Phase Diagram of Hadronic Matter Rajagopal and Wilczek, hep-ph/-0011333 Crossover Plasma ≡ ionized gas which is macroscopically neutral & exhibits collective effects Usually plasmas are e.m., here color forces 1st/2nd order

  5. The Phase Transition in the Laboratory t ~12 fm/c soft physics regime hard (high-pT) probes Chemical freezeout (Tch  Tc): inelastic scattering ceases Kinetic freeze-out (Tfo Tch): elastic scattering ceases

  6. 2 concentric rings of 1740 superconducting magnets 3.8 km circumference counter-rotating beams of ions from p to Au p+p @ √smax=500 GeV p+A @ √smax= 200 GeV A+A @√sNN = 200GeV L = 2·1026 cm-2 s-1 Relativistic Heavy-Ion Collider (RHIC) @ BNL BRAHMS PHOBOS PHENIX STAR Long Island • 2000-2005 • p+p (polarized): sNN=200, 410 GeV • d+Au: sNN=200 GeV • Cu+Cu: sNN= 62, 200 GeV • Au+Au: sNN= 20, 62, 130, 200 GeV

  7. Paddle Trigger Counter TOF Spectrometer Octagon+Vertex Ring Counters The RHIC Experiments STAR PHENIX BRAHMS PHOBOS (terminated)

  8. z y x Reaction plane Geometry of a Heavy-Ion Collision Non-central collision “peripheral” collision (b ~ bmax) “central” collision (b ~ 0) Number of participants (Npart):number of incoming nucleons (participants) in the overlap region Number of binary collisions (Nbin): number of equivalent inelastic nucleon-nucleon collisions Nbin Npart

  9. Peripheral Collision Color  Energy loss in TPC gas

  10. Central Collision

  11. Central Peripheral Large Particle Production 19.6 GeV 130 GeV 200 GeV Phobos dNch/dh h • Central: 200 GeV Au+Au: ~4800 charged particles (~20 in pp) • dNch/dy|y=0 / NPart.-Paar ~ 4  ~2.5 in p+p • Plateau at y ~ 0  boost invariant at least in small region • Not simply a superposition of p+p !!

  12. EnoughEnergy to Heat the System Stopping: Energy Loss of colliding nucleons Analysis of net-proton (~ net-baryon) spectra (p -p): Out of a maximum energy of 39.4 TeV in central Au-Au reactions, 26 TeV is made available for heating the system.

  13. Observed Energy Density Exceed Critical Density Bjorken-Formula for Energy Density: Time it takes to thermalize system (t0 ~ 1 fm/c) R~6.5 fm pR2 Central Collisions: 130 GeV: eBJ 4.6 GeV/fm3 200 GeV: eBJ  5.0 GeV/fm3 ~30 times normal nuclear density~ 5 times above ecritical from lattice QCD

  14. Particle Yields in Equilibrium at Chemical Freezeout • Statistical Thermal Models: • Assume thermally (constant Tch) and chemically (constant ni) equilibrated system at chemical freeze-out • System composed of non-interacting hadrons and resonances • Obey conservation laws: Baryon Number, Strangeness, Isospin • Given Tch and  's (+ system size), ni's can be calculated in a grand canonical ensemble Yields and ratios of particles can be described very well by a system in equilibrium with: T 175 MeV  TC mB 30 MeV Resonance suppression Strangeness enhancement STAR

  15. Hydrodynamics: Modeling High-Density Scenarios • Assumes local thermal equilibrium (zero mean-free-path limit) and solves equations of motion for fluid elements (not particles) • Equations given by continuity, conservation laws, and Equation of State (EOS) • EOS relates quantities like pressure, temperature, chemical potential, volume • Most hydro calculation  no viscosity Kolb, Sollfrank & Heinz, hep-ph/0006129 lattice QCD input

  16. light 1/mT dN/dmT heavy mT Strong Collective Radial Expansion • Different spectral shapes for particles of differing mass strong collective radial flow Au+Au central , √s = 200 GeV purely thermal source T explosive source light 1/mT dN/dmT T,b heavy mT Hydro pQCD mT = (pT2 + m2)½ Good agreement with hydrodynamic prediction for soft EOS (QGP+HG) • RHIC: Tfo~ 100 MeV •  bT  ~ 0.55 c

  17. Kinetic Freeze-Out @ 200 GeV • Strong collective radial expansion at RHIC • high pressure • high rescattering rate Slightly model dependent here: blastwave model Radial flow bT: increases with √s and centrality Freeze-out Temperature Tfo: decreases with centrality, constant in √s (bigger systems freeze out later)

  18. Almond shape overlap region in coordinate space Interactions/ Rescattering Anisotropy in momentum space t2 t3 t1 t4 Azimuthal Anisotropy of Emission: Elliptic Flow Elliptic flow observable sensitive to early evolution of system Mechanism is self-quenching Large v2 is an indication of early thermalization dN/df ~ 1+2 v2(pT)cos(2f) + …. f = atan(py/px) v2= cos2f v2: 2nd harmonic Fourier coefficient in dN/d with respect to the reaction plane Au+Au at b=7 fm P. Kolb, J. Sollfrank, and U. Heinz Equal energy density lines

  19. Strong Elliptic Flow Observed Hydrodynamical models with soft Equation-of-State (EOS) describe data well for pT (< 2.5 GeV/c) v2(p) > v2(K) > v2 (p) ~ v2(L)  compatible with early equilibration ... Contrast to lower collision energies where hydro overpredicts elliptical flow

  20. Hydro Limits: Like a Perfect Liquid? First time hydro- dynamics without any viscosity describes heavy ion reactions: Thermalization time t = 0.6 fm/c, Energy Density: e=20 GeV/fm3 U. Heinz, nucl-th/0407067 Hydro Limit (RHIC) e=spatial eccentricity = y2-x2/y2+x2 S=overlap area

  21. Analogy in Atomic System • Same phenomena observed in gases of strongly interacting atom (Gehm et al. Science 298 (2002) 2179) • Gas of trapped 6Li atoms: excite Feshbach resonance via magnetic field (38th vibrational Li2 state)  0 energy, huge cross-section  explodes hydrodynamically, shows elliptic flow The RHIC fluid behaves like this, that is, a strongly coupled fluid.

  22. Quark Coalescence in Flow The complicated observed flow pattern in v2(pT) for hadrons is predicted to be simple at the quark level underpT → pT /n v2 → v2 / n , n = (2, 3) for (meson, baryon) If the flow pattern is established at the quark level Works for p, (p), K0s, , , W v2s ~ v2u,d ~ 7% STAR D. Molnar, S.A. Voloshin Phys. Rev. Lett. 91, 092301 (2003) V. Greco, C.M. Ko, P. Levai Phys. Rev. C68, 034904 (2003) R.J. Fries, B. Muller, C. Nonaka, S.A. Bass Phys. Rev. C68, 044902 (2003) Z. Lin, C.M. Ko Phys. Rev. Lett. 89, 202302 (2002)

  23. New: v2 of Non-Photonic Electrons Semileptonic D decays • Indication of strong non-photonic electron v2 • consistent with v2(c) = v2(light quark) Puzzeling: Relaxation time for charm 7  larger than for light quarks (t > 10 fm/c) Need large scattering cross-sections!!! Phenix : Min. Bias Star: 0-80% STAR: stat. errors only

  24. q q c a b d Probing the Dense Matter • Using probes that are: • Auto-generated  initial hard scatterings • Traverse the medium  interact with the medium • Calculable in pQCD • Calibrated  measured in p+p • These features no available prior to RHIC

  25. Jets at RHIC? Au+Au ??? (STAR@RHIC) pp jet+jet (STAR@RHIC) No! Measure leading hadrons that make out the high-pT spectra Hopeless?

  26. How to Measure? Compare Au+Au with p+p Collisions  RAA A+A yield Nuclear Modification Factor: p+p cross section <Nbinary>/sinelp+p R < 1 at small momenta R = 1 baseline expectation for hard processes R > 1 “Cronin” enhancements (as in pA)R < 1: Suppression

  27. “NN scaling” in Au+Au @ 200 GeV: Direct Photons Direct photon production in Au+Au (all centralities) consistent with p+p incoherent scattering (“NN-scaled” pQCD) predictions: Direct photon production in Au+Au unmodified by QCD medium. Submitted to PRL nucl-ex/0503003

  28. High-pT p+p Baseline Data Well Described by pQCD • Good theoretical (NLO pQCD) description: p+p p0 Xp+p h±X (non singly diffractive) (PDF: CTEQ6M) PHENIX Collab. PRL91, 241803 hep-ex/0304038 KKP FF Kretzer FF Well calibrated (experimentally & theoretically) p+p references at hand

  29. Suppressed High-pT Hadroproduction in Au+Au @ RHIC ! • Au+Aup0 X (peripheral) Au+Au p0 X (central) • Peripheral data agree well with Strong suppression in • p+p (data & pQCD) plus Ncoll-scaling central Au+Au collisions D.d'E, nucl-ex/0401001

  30. Suppression of Leading Hadrons • Combined data from Runs 1-3 at RHIC on p+p, Au+Au and d+Au collisions establish that a new effect (a new state of matter?) is produced in central Au-Au collisions Au + Au Experiment d + Au Control Experiment Final Data Preliminary Data Au+Au: for pT > 5 GeV/c  factor 5 suppression independent of pT

  31. Partonic Energy Loss: Theory • Elastic scattering (Bjorken 1982): • Gluon radiation (factor ~ 10 larger) • Multiple final-state gluon radiation off the produced hard parton induced by the traversed dense colored medium • Mean parton energy loss  medium properties: • DEloss ~ gluon (gluon density) • DEloss ~ DL2 (medium length)  ~ DL with expansion • Formalisms: BDMPS (thick plasma), GLV (thin plasma) • Deduced initial gluon density at t0 = 0.2 fm/c: • dNglue/dy ≈ 800-1200 • e≈ 15 GeV/fm3 (in static medium) • Other models can be ruled out: • dE/dx in hadronic medium (pT dependence) • Color-Glass-Condensate (d+Au not suppressed at y=0)

  32. RAA pT [GeV/c] New: Heavy Quark Energy Loss Measure charm energy loss via electrons from semileptonic D decays • Gluon radiation suppressed for heavy quarks in dead cone: q < m/E • Strong in vacuum: Dokshitzer, Kharzeev: PLB 519(2001)199 • Lesser in medium: Armesto, Salgado, Wiedemann: PRD 69(2003)114003 • Observe suppression at high pT • reasonable agreement with theoretical models incorporating heavy quark energy loss • can differentiate between scenarios • Note • data may contain significant contribution from b decays for pT ≥ 4 GeV/c M. Djordjevic et al., hep-ph/0410372 N. Armesto et al. hep-ph/0501225

  33. peripheral Au+Au collisions central Au+Au collisions min. bias p+p collisions pedestal and flow subtracted trigger Phys Rev Lett 90, 082302 ? Jets and Two-Particle Azimuthal Distributions p+p  dijet Near side Df 0: p+p, d+Au, Au+Au similar Back-to-back Df p : Au+Au suppressed relative to p+p and d+Au • Trigger: highest pT track, pT>4 GeV/c • Δ distribution: 2 GeV/c < pT < pTtrigger • normalize to number of triggers Df 0: peripheral and central Au+Au similar to p+p Df p: strong suppression of back-to-back correlations in central Au+Au Suppression of back-to-back correlations in central Au+Au is a final-state effect

  34. Di-Jet Tomography: Angel with Reaction Plane Matters • Au+Au: Away-side suppression is larger in the out-of-plane direction compared to in-plane

  35. Jet correlations in proton-proton reactions. Strong back-to-back peaks. Jet correlations in central Gold-Gold. Away side jet disappears for particles pT > 2 GeV Jet correlations in central Gold-Gold. Away side jet reappears for particles pT>200 MeV Different View of Jet Quenching Azimuthal Angular Correlations

  36. Consistent with speed of sound from lattice QCD. Mach Cone measures the speed of sound. Reaction of the Medium How does the near-perfect liquid react to this large energy deposition? Color shock wave?

  37. So is there a QGP at RHIC ? • Experiments & Theory provide overwhelming evidence for new state of matter • Extreme initial conditions (hydrodynamics, lattice, pQCD) • dNglue/dy ≈ 1000 • e≈ 15-20 GeV/fm3 • Hydrodynamic behavior (collective flow, low-pT spectra) • Chemical Equilibrium (particle yields) • Jet suppression (opacity, extreme medium density) • This state of matter is not what we expected when we started our journey • no weakly interacting plasma (wQGP) • no phase transition observed (no latent heat, discontinuities, spikes) • New state of matter seems to be strongly interacting, nearly-perfect fluid (sQGP) • Currently a cross-over is more likely than a 1st or 2nd order phase transition • Next decade should be very exciting (GSI + RICH-II + eRHIC + LHC) • Understanding perfect liquid behaviour • Is there a weakly coupled state (wQGP) in the initial state at LHC ? • Understand the nature of deconfinement and the degrees of freedom

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