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Bulk Particle Production A Global View

Bulk Particle Production A Global View. Gunther Roland. Parameters Concepts. How many. needed to describe average collision?. Bulk Properties. Single Au+Au Collision O(10 4 ) 4-Vectors. Provide background (5 - 15% accuracy) against which we can search for structure.

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Bulk Particle Production A Global View

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  1. Bulk Particle Production A Global View Gunther Roland

  2. Parameters Concepts How many needed to describe average collision? Bulk Properties Single Au+Au Collision O(104) 4-Vectors Provide background (5 - 15% accuracy) against which we can search for structure

  3. Global Observable Control Parameter “Global Observables” need to be understood in context Global Observables

  4. Drees, QM ‘01 sinel=42 mb (RHIC) sinel=33 mb (SPS) sinel=21 mb (low AGS) PHOBOS Glauber MC Control Parameters System-Size Energy Also: Different systems (different nuclei, pp, pA, e+e-)

  5. Bulk Properties

  6. Energy dN/dh Centrality Pseudorapidity I. Particle Density near Mid-Rapidity How does Density at 90o change with Energy and Centrality? Please, see poster by Sasha Milow !

  7. “Midrapidity Density” Particle Density near Mid-Rapidity Beware of the Jacobian! dN/dh = <b> dN/dy

  8. Particle Density near Mid-Rapidity Logarithmic Rise with Collision Energy

  9. Lexus (Kapusta,Jeon) Incoherent p+p superposition CGC (McLerran, Venugopalan) “Coherence” of Hardon Production Particle Density near Mid-Rapidity Models prior to RHIC

  10. 200 GeV 130 GeV 19.6 GeV Surprising Lack of Energy Dependence Centrality Dependence at |h| < 1

  11. Energy dN/dh Centrality Pseudorapidity II. 4-p Multiplicity <Nch> How does Integral over 4-p, <Nch>, change with Energy and Centrality?

  12. Nch vs Npart in d+Au see talk by Rachid Nouicer PHOBOS preliminary <Nch>pp*Npart PHOBOS preliminary d+Au Multiplicity proportional to p+p Multiplicity * Npart

  13. Nch vs Npart in Au+Au 200 GeV central <Nch>e+e-*Npart 200 GeV dN/dh/<1/2 Npart> peripheral 130 GeV central peripheral 19.6 GeV 19.6 GeV Pseudorapidity Au+Au Multiplicity proportional to Npart

  14. Energy dN/dh Centrality Pseudorapidity III. Shape of dN/dh Distributions How does Shape of dN/dh (dN/dy) change with Energy? Reaching the Central Plateau?

  15. E895 E895 E895 BRAHMS prel. NA49 NA49 Boost-invariance? p+ dN/dy spectra Single Gaussian fits from 2 to 200 GeV

  16. Landau Hydrodynamics Carruthers, Duong-Van on pp data in 1973:

  17. <Nch> vs sqrt(s) revisited Carruthers, Duong-Van on pp and e+e- data in 1983:

  18. IV. Spectrum of Produced Hadrons Temperature Chemical Potential Mass Quantum Numbers Yield Hagedorn, Becattini, Braun-Munzinger, Cleymans, Letessier, Mekijan,Rafelski, Redlich,Stachel, Tounsi

  19. Spectrum of Produced Hadrons

  20. “Thermal Fit” Parameters vs sqrt(s)

  21. V. Transverse Dynamics

  22. Structure in Inverse Slope vs sqrt(s)

  23. Summary • Data can indeed by reduced efficiently • We’re doing Thermodynamics! • Total Multiplicity • Proportional to Npart • Rises like s1/4 from mid-SPS Energy Range • p dN/dy Distributions • Single Gaussian with width s2 ~ 0.5 ln(s/4mp) • Statistical Fits describe Hadron Abundances • Systematic Evolution, Limiting Temperature • Correspondence with other ‘Hadronic’ Systems • p+p, p+A, e+e- • Max Entropy Evolution from Dense Initial State • How is the Initial State Prepared? • Baryon Number Transport?

  24. x + Coincidence? This is a cartoon! (so far) Model H pp Nmin - Nmax 5.0 Predictions dN/dh||h|<1 /<0.5 Npart>(200 GeV) e+e- A+A 3.7 Ratio RRHIC/SPS 1.8 2.5

  25. Particle Ratios in d+Au: p/p vs Centrality Au+Au Phys. Rev. C 67, 021901R (2003) nucl-ex/0309013 - submitted to PRC Constant p/p ratio vs centrality Disagreement with expectations/models

  26. Npart scaling?

  27. Rapidity Distributions at 200 GeV PHOBOS QM’02, Steinberg q q 200 GeV Central Au+Au e+e- measures dN/dyT(rapidity relative to“thrust” axis) h yT AA/pp ~ 1.4-1.5 Surprising agreement in shape between AA/e+e- /pp Correspondence between perturbative and non-perturbative approaches?

  28. Transverse Energy near h=0 PHENIX QM ‘02 nucl-ex/0209025 PHENIX QM ‘02 nucl-ex/0209025 • dET/dh exhibits smooth rise vs sqrt(s) • Surprisingly, <ET> per particle at h=0 constant • even though p+p spectra get much harder with sqrt(s)

  29. Transverse Energy near h=0 STAR QM ‘02 nucl-ex/02111021 PHENIX QM ‘02 nucl-ex/0209025 D<ET> < 10% D<pT> ~ 20%

  30. Net Proton dN/dy

  31. Transverse Energy vs Npart STAR QM ‘02 nucl-ex/0211021, poster M. Calderon PHENIX QM ‘02 nucl-ex/0209025 STAR prel. 130 GeV 200 GeV • dET/dh and <pT> independent of Npart above Npart ~50

  32. Boost-invariance?

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