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ARGONNE NATIONAL LABORATORYBirger Back, Alan WuosmaaBROOKHAVEN NATIONAL LABORATORYMark Baker, Donald Barton, Alan Carroll, Nigel George, Stephen Gushue, George Heintzelman, Burt Holzman, Robert Pak, Louis Remsberg, Peter Steinberg, Andrei SukhanovINSTITUTE OF NUCLEAR PHYSICS, KRAKOWAndrzej Budzanowski, Roman Holynski, Jerzy Michalowski, Andrzej Olszewski, Pawel Sawicki, Marek Stodulski, Adam Trzupek, Barbara Wosiek, Krzysztof WozniakMASSACHUSETTS INSTITUTE OF TECHNOLOGYMaa24
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1. Recent Results from PHOBOS at RHIC Robert Pak
Brookhaven National Laboratory
for the PHOBOS Collaboration
PANIC 2002
Osaka, Japan
Sept. 30th, 2002
3. PHOBOS Apparatus
4. Kinematics: many ways to slice pz
6. Particle Spectra
7. Why charged particle production? Fundamental handle on the initial state
Upper bound on initial entropy density
Entropy does NOT require equilibrium
Initial gluon density
Constrains subsequent evolution
Freezeout entropy density
8. Pseudorapidity Density Distributions Au+Au collisions at ?s = 19.6, 130, 200 GeV
dN/dh for |h| < 5.4 over full azimuth
Top 50% of total cross section (Npart~ 65 - 360)
Data at 56 GeV only for central density at |h| < 1
10. Centrality Dependence of Central Density
11. Limiting Fragmentation
12. Centrality Dependence of ?Nch?
13. Remove the Leading Proton Effect
14. Comparison of áNchń vs. Energy
15. Total Multiplicity vs. Beam Energy
16. Azimuthal Angular Distributions
17. 130 GeV errors not shown
Similar to 130 GeV results
Within errors, difficult to distinguish whether or not v2 is saturated or scales with the increase in multiplicity as the energy increases.130 GeV errors not shown
Similar to 130 GeV results
Within errors, difficult to distinguish whether or not v2 is saturated or scales with the increase in multiplicity as the energy increases.
18. Here we integrate over h+ and h-Here we integrate over h+ and h-
19. Again, little changed from 130 GeVAgain, little changed from 130 GeV
20. Again, little changed from 130 GeVAgain, little changed from 130 GeV
21. Not boost invariant over broad h range
Limiting fragmentation confirmed for AA
Total yields in AA scale primarily with Npart
Surprising similarity between AA and e+e-
Conclusions