  I will review RHIC data with respect to the intriguing possibility that the
hadron production mechanism in the produced partonic medium might be different
than in vacuum. I will use the measurements of collective features, such as
flow and quenching of identified particles, to show that different regions of
the particle momentum spectrum are likely populated through different
mechanisms, and that the medium seems to play an important role in
hadronization. Finally I will address the question whether the different
initial conditions achievable in heavy ion collisions at LHC energies, compared
to RHIC, might affect the properties of the deconfined quark-gluon phase and
its hadronization to baryonic matter.
