Collective Phenomena in

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Collective Phenomena in Heavy Ion Collisions

• Ágnes Nyíri
• László P. Csernai
• Etele Molnár
• Karolis Tamosiunas
• Volodymyr Magas (University of Valencia)
• Dan Strottman (Los Alamos)
• Bernd Schlei (Los Alamos)

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Introduction
Why to collide heavy ions?
nuclear physics, particle physics, astrophysics,
condensed matter physics astronomy
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QGP A new state of matter
The combined data coming from the seven
experiments on CERN's Heavy Ion programme have
given a clear picture of a new state of matter. .
. . We now have evidence of a new state of
matter where quarks and gluons are not confined.
There is still an entirely new territory to be
explored concerning the physical properties of
quark-gluon matter. L. Maiani, 2000

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Importance of fluid dynamics
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Importance of fluid dynamics

• Gyulassy - QGP stands on 3 legs,
• 1st is the flow
• EoS and Phase Transition are properties
  of locally equilibrated and thermalized
  matter,
• so we need some proof that the matter
  reached this stage.

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Global Flow Patterns
Directed Transverse flow
3rd flow component (anti - flow)
X
b
Z
Squeeze out
Elliptic flow
Spherical flow
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Definition of flow

• Fourier expansion of the azimuthal
  distribution of particles
• Thus

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Success in reproducing v2
I
Radial and Elliptic flow at central rapidity
strong dominant.
Simple, 21 dim. FD models can fit data.

String hadron cascade models usually do not.
ZabrodinSQM2004
v2(pt) data are well fitted,
however, v2(y) data (PHOBOS) are not!!!
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Success in reproducing v2
NEW ! Phenix v2 scaling data. Strong proof of
FD behaviour quark recombination. Analyzed and
reproduced in more FDmodels.
HeinzSQM2004
D.MolnarSQM2004
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3rd flow component and QGP

• Csernai Röhrich Phys.Lett.B458(99)454
  observed a 3rd flow component at SPS energies,
  not discussed before.
• Also observed that in ALL earlier fluid dynamical
  calculations with QGP in the EoS there is 3rd
  flow component.
• The effect was absent without QGP.
• In string and RQMD models only peripheral
  collision showed the effect (shadowing).

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Initial conditions Freeze Out
FD is applicable at the middle stages of a heavy
ion reaction. The Initial State and final Freeze
Out must be described in another way.
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Initial state
Magas, Csernai, Strottman, Phys. Rev. C64 (01)
014901
3rd flow component
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Flow at RHIC Energy-density TemperatureTech.
Editor Production András Csernai (12)
AuAu ECM65 GeV/nucl. b0.5 bmax As0.08
gt s10 GeV/fm
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Freeze Out on a Hypersurface Axonometric view
(Bernd Schlei)
T 139 MeVsurface
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Freeze Out on a Hypersurface In plane view
(Bernd Schlei)
X
Z
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v1 results
Full Experimental detection of flow is alsovery
delicate many complex flow patternse.g.
v2, dN/dy, are notpublished yet in thisy range.
No modelsfit these data !!!
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Outlook
Several experimental methods exist, and it takes
time and effort to analyse the data in a best
way.
NyiriSQM2004
v1,v2 vs. pt,y dN/dy, dN/dpt simultaneous
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Outlook
Very complex and delicate theoretical analysis
is needed 31 dim. FD, with goodinitial state
and FO description. We expect that these
experiments with more detailed theoretical
analysis will provide a large amount of valuable
information, more than up to now EoS, transport
coeff., string tension, initial dynamics,
hadronization dynamics,