Köln 2004 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 7: Heavy Ions I
HK 7.7: Vortrag
Montag, 8. März 2004, 17:45–18:00, F
Anisotropies in RHIC spectra - probing the detailed dynamics — •Peter Kolb — Department of Physics and Astronomy, SUNY Stony Brook, Stony Brook, NY 11794, USA — Physik Department, Technische Universität München, D-85747 Garching
Anisotropies in the momenta spectra of non-central relativistic heavy-ion collisions are sensitive on the collective expansion dynamics at the earliest stages of the reaction. In the transverse plane, the azimuthal dependence of the particle distribution is usually characterized through v2 = ⟨ cos2 φ ⟩, the second coefficient of the corresponding Fourier expansion.
I will present arguments from which we can expected that also higher order terms of the Fourier expansion in RHIC collisions reach an observable magnitude of a few per cent, and that they carry valuable information on details of the expansion dynamics. In order to give quantitative estimates, I study different model calculations, spanning from hydrodynamic expansion to the complementary geometric limit of fully quenched jets. Furthermore the influence of the equation of state and geometry of the initial state is discussed. I conclude, that although higher harmonics are small, they are very sensitive on details of the model parameters and are thus of great potential to extract quantitative statements from the data. I will discuss recently published results on v4 in Au+Au collisions by STAR [2] which appear to be in good agreement with earlier hydrodynamic predictions [1].
[1] P.F. Kolb, Phys. Rev. C 68 (2003) 031902(R). [2] J. Adams et al. nucl-ex/0310029.