Collective Flow in Ultra-relativistic Collisions

The Fluid Dynamical (FD) models are considered to be a good description of heavy ion reactions with higher collision energies. Recent results indicate that the collective flow develops in the Quark Gluon Plasma (QGP) phase, what results in the Constituent Quark Number (NCQ) scaling of the flow. At the same time, between the deconfined ideal QGP and the Hadronic Matter, a so-called “Quarkyonic Matter” is predicted, where the dominant degrees of freedom are quarks. In FD model we assume the formation of the quarkyonic matter in the final Freeze Out (FO) stage, which includes deconfinement and the simultaneous formation of constituent quarks. Then we reach the conclusion that collective flow must have frozen out early when the quarks were the dominant constituents of matter, and the final hadron masses are reached subsequently.