Collective Flow Art Poskanzer Exploring the secrets of the universe Color by Roberta Weir
Photos macroscopic nuclear physics Poskanzer, Swiatecki, and Seaborg 1982 (1986) 1998
Spectator-Participant Picture 1973 Abrasion and Ablation of Heavy Ions, J.D. Bowman, W.J. Swiatecki, and C.F. Tsang, LBL-2908 (1973)
Fireball G.D. Westfall et al., Phys. Rev. Letters 37, 1202 (1976)
Centrality Dependence z z y y x x Y Y X X Peripheral Collision (near) Central Collision
Transverse Plane y x Danielewicz <y2> - <x2> ε = <y2> + <x2> H. Wieman (2005) around the beam axis S = π x y
Elliptic Flow Animation by Jeffery Mitchell (Brookhaven National Laboratory)
Nuclear Collisions Bevalac SPS RHIC Mass Energy in cm 1975 Explored to date only on the axes. W.J. Swiatecki, Bevalac Upgrade Proposal, 1975.
Kinds of Flow mainly spectator matter self quenching early time temperature
Plateau 1984 Temperature or Pressure direct photons elliptic flow Beam Energy W. Swiatecki (1984)
v2 / NA49, C. Alt et al., Phys. Rev. C 68 034903 (2003) S.A. Voloshin and A.M. Poskanzer, Phys. Letters B 474, 27 (2000)
Azimuthal Flow Angle py px S. Voloshin and Y. Zhang, Z. Phys. C 70, 665 (1996)
Fourier Harmonics Voloshin Event plane resolution correction made for each harmonic Unfiltered theory can be compared to experiment! S. Voloshin and Y. Zhang, hep-ph/940782; Z. Phys. C 70, 665 (1996) See also, J.-Y. Ollitrault, arXiv nucl-ex/9711003 (1997) and J.-Y. Ollitrault, Nucl. Phys. A590, 561c (1995)
Methods of Analysis • Pair-wise • Standard • Scalar Product • q-dist • Cumulant • Lee-Yang Zeros
Directed and Elliptic Flow at the SPS pions protons y pt NA49, C. Alt et al., PRC 68, 034903 (2003)
STAR
First RHIC Elliptic Flow hydro Snellings Voloshin Poskanzer First paper from STAR 130 GeV/A Au+Au 22 k events Data approach hydro for central collisions STAR, K.H. Ackermann et al., PRL 86, 402 (2001)
Elliptic Flow vs. Beam Energy 25% most central mid-rapidity all v2 bounce-off In-plane elliptic flow squeeze-out six decades A. Wetzler (2005)
Directed Flow from Mixed Harmonics 2nd har. event plane N-particle cumulants v1{EP1,EP2} v1{3} Removes nonflow Uses best determined event plane STAR, J. Adams et al., PRC submitted (2005)
v1 from Spectator Neutrons Zero-Degree Calorimeter Shower Max Detector for transverse deflection of spectator neutrons A. Tang, STAR
Quark Coalescence n = number of constituent quarks D. Molnar and S.A. Voloshin, Phys. Rev. Letters 91, 092301 (2003) STAR, Phys. Rev. C 72, 014904 (2005)
Higher Harmonics vn= 1.2 v2n/2 more details of the event shape in p space quarks have v4 J. Adams et al., PRL 92, 062301 (2004)
Conclusions from Flow • Hydrodynamics at top RHIC Energy • Thermalization • Parton Coalescence • Partonic Phase • Thermalized Partonic Phase • Quark-Gluon Plasma
