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Peter Kolb, CIPANP03, May 22, 2003Peter Kolb, CIPANP03, May 22, 2003 what we learn from hydro 11
What did we learn, andwhat will we learn from Hydro
CIPANP 2003New York City, May 22, 2003
Department of Physics and AstronomyState University of New YorkStony Brook, NY 11794
with support from theAlexander von Humboldt Foundation
Peter F. Kolb
Peter Kolb, CIPANP03, May 22, 2003Peter Kolb, CIPANP03, May 22, 2003 what we learn from hydro 22
Modeling the Expansion Dynamics
microscopic view macroscopic view vs
u
T
t
scattering of partons and hadrons
kinetic transport equations
collision terms
formalism:
continuity equations
energy, momentum conservation
equation of stateF. Karsch, Nucl. Phys. A 698 (2002) 1999U. Heinz, Nucl. Phys. A 685 (2001) 414
Peter Kolb, CIPANP03, May 22, 2003Peter Kolb, CIPANP03, May 22, 2003 what we learn from hydro 33
Hydrodynamic Evolution (b=0)
Equations of Motion:
+ Equation of State:
+ Initial Configuration:from an optical Glauber calculation
0 = 0.6 fm
here a resonance gas EoS for Tcrit < 165 MeVwith mixed phase and ideal gas EoS above
Peter Kolb, CIPANP03, May 22, 2003Peter Kolb, CIPANP03, May 22, 2003 what we learn from hydro 44
Evolution of Radial Flow
radial flow at fixed r as a function of time radial flow at fixed time as a function of r
+ mixed phase obstructs the generation of transverse flow+ the transverse flow profile rapidly adopts
a linear behavior vr = r with ~ 0.07 fm-1
PFK, nucl-th/0304036
Peter Kolb, CIPANP03, May 22, 2003Peter Kolb, CIPANP03, May 22, 2003 what we learn from hydro 55
Particle Spectra of Central Collisions: Au+Au @ 200 A GeV
Hydro parameters:0 = 0.6 fm/cs0 = 110 fm-3
s0/n0 = 250Tcrit=Tchem=165 MeV
Data: PHENIX: NPA715(03)151; STAR: NPA715(03)458; PHOBOS: NPA715(03)510; BRAHMS: NPA715(03)478Hydro-calculations including chemical potentials: PFK and R. Rapp, Phys. Rev. C 67 (03) 044903
Tdec=100 MeV
Peter Kolb, CIPANP03, May 22, 2003Peter Kolb, CIPANP03, May 22, 2003 what we learn from hydro 66
Single Particle Spectra: STAR collab., Nucl. Phys. A 715 (2003) 470c
Hydro calculation as in PFK and R.Rapp, Phys. Rev. C 67 (2003) 044903
The Omega resonance shows as strong transverse flow as the lighter hadrons. It appears to fully participate in the collective
expansion in the partonic as well as in the hadronic stage
Peter Kolb, CIPANP03, May 22, 2003Peter Kolb, CIPANP03, May 22, 2003 what we learn from hydro 77
Even Multistrange Particles FlowJavier Castillo for the STAR collaboration at SQM 2003
VERY PRELIMINARY
??
The Omega picks up flow from both the partonic as well as the hadronic phase and falls right on the hydro-systematics!
According to Batsouli, Kelly Gyulassy and Nagle (Phys. Lett. B 557 (2003) 26), even the D-meson spectrum is as flat as expected from hydro (however PYTHIA gives about the same result !)
See also Zhangbu Xu’s talk for 200 GeV, Tuesday May 20
Peter Kolb, CIPANP03, May 22, 2003Peter Kolb, CIPANP03, May 22, 2003 what we learn from hydro 88
Still more exotic: Mesons with Heavy Quarks
PHENIX collab: Phys. Rev. Lett. 88 (2002) 192303S.Batsouli, S.Kelly, M.Gyulassy, J.L.Nagle, Phys. Lett. B 557 (2003) 26
Single electron spectra from charm decay can be described by PYTHIA, as well as by assuming transverse flow of D and B mesons.
Elliptic flow will make a clear statement!
(And such measurements are coming!)
Peter Kolb, CIPANP03, May 22, 2003Peter Kolb, CIPANP03, May 22, 2003 what we learn from hydro 99
Transverse Momentum and Trans. EnergyPHENIX collab., Nucl. Phys. A 715 (2003) 151c PHENIX collab., Nucl. Phys. A 715 (2003) 151c
Transverse momenta as function of centrality are wellunder control as long as the collisions are not too peripheral.
Transverse energy agrees for all centralities.
Peter Kolb, CIPANP03, May 22, 2003Peter Kolb, CIPANP03, May 22, 2003 what we learn from hydro 1010
Evolution of Non-Central Collisions
spatial eccentricity
momentumanisotropy
evolution of the energy densityinitial energy density distribution
PFK, J. Sollfrank and U.Heinz, PRC 62 (2000) 054909(here b=7 fm)
initial energy density distribution
Peter Kolb, CIPANP03, May 22, 2003Peter Kolb, CIPANP03, May 22, 2003 what we learn from hydro 1111
Elliptic Flow at RHIC (130):Heinz, PFK, NPA 702(02)269; Huovinen et al. PLB 503(01)58;
Teaney et al. PRL 68(01)4783; Hirano, PRC 65(01)011901
Mass, momentum and centrality dependence are well described up to pT ~ 2 GeV and b ~ 7 fm
Over 99 % of the emitted particles follow hydro systematics
ST
AR
col
lab.
, PR
L 8
7 (2
001)
182
301
ST
AR
, J.
Phy
s. G
28
(200
2) 2
0
Peter Kolb, CIPANP03, May 22, 2003Peter Kolb, CIPANP03, May 22, 2003 what we learn from hydro 1212
Elliptic flow requires Rapid ThermalizationPFK, J. Sollfrank and U. Heinz, PRC 62 (2000) 054909
Free flow for an interval t changes the initial distribution function .For massless particles in the transverse plane ( ):
Reduced spatial anisotropy
as , the elliptic flow is reduced accordingly. With typical dimensions of non-central collisions, one obtains a reduction of 30 % for t = 2 fm/c.
Peter Kolb, CIPANP03, May 22, 2003Peter Kolb, CIPANP03, May 22, 2003 what we learn from hydro 1313
Elliptic Flow requires Strong RescatteringPFK et al., PLB 500 (2001) 232; D. Molnar and M. Gyulassy, NPA 698 (2002) 379
Cross-sections and/or gluon densities of at some 10 to 80 times the perturbative estimates are required to deliver sufficient anisotropies.
At larger pT the experimental results (as well as the parton cascade) saturate, indicating insufficient thermalization of the rapidly escaping particles to allow for a hydrodynamic description.
Peter Kolb, CIPANP03, May 22, 2003Peter Kolb, CIPANP03, May 22, 2003 what we learn from hydro 1414
Sensitivity on the Equation of State
Teaney, Lauret, Shuryak, nucl-th/0110037PFK and U. Heinz, nucl-ex/0204061
The data favor an equation of state with a soft phase and a latent heat e between 0.8 and 1.6 GeV/fm3
Peter Kolb, CIPANP03, May 22, 2003Peter Kolb, CIPANP03, May 22, 2003 what we learn from hydro 1515
Elliptic Flow at Finite RapidityT. Hirano and K. Tsuda, nucl-th/020868
Boost invariance and thermodynamic concepts seem to be justified
over a pseudo-rapidity interval from -1.5 < 1.5
Observables at larger rapidities:
hold pre-equilibrium information ( directed flow!) operate at higher B ( close to the critical point!)
---
J.B
ower
s, K
.Raj
agop
al, h
ep-p
h/02
0916
8
Peter Kolb, CIPANP03, May 22, 2003Peter Kolb, CIPANP03, May 22, 2003 what we learn from hydro 1616
Hydrodynamics is THE TOOL to study the thermodynamic properties (i.e. the equation of state) of nuclear matter under extreme conditions
Elliptic flow is THE OBSERVABLE to study the thermodynamic features of the equation of state from the earliest stages of the collision
The data suggest rapid thermalization and favor an equation of state with a soft region of width e~ 1 GeV/fm3
Summary 1: What Have we Learned
Peter Kolb, CIPANP03, May 22, 2003Peter Kolb, CIPANP03, May 22, 2003 what we learn from hydro 1717
with the prerequisites for a hydrodynamic description given, and the many precise results on soft observables we can:
Which particles flow? Multistrange? Charm?
Summary 2: What Will we still Learn
study the degree and breakdown of thermalization
(in b, pT, sNN), and quantify viscosity effects (i.e
fundamentals of QCD and hadronic physics)
get more quantitative to extract information on the equation of state (even at varying chemical potential)
The bulk of the system follows hydrodynamics. Use this information as background for rarer observables and hard processes to answer:
How does the dog wag its tail ? (see M. Gyulassy’s talk)