Pseudorapidity shape of elliptic flow as signature for fast equilibration in relativistic heavy-ion collisions at energies up tosNN=200GeV

Abstract

The implications of parton recombination processes on the dynamics of ultrarelativistic heavy-ion reactions are investigated. To do so, the quark-gluon string transport model has been extended for partonic recombination and fusion processes. Parton recombination leads to short equilibration times and improves significantly on the theoretical description of measured directed and elliptic flow, i.e., ${v}_{1}$ and ${v}_{2}$, distributions in Au+Au collisions at $\sqrt{{s}_{\mathit{NN}}}=200\phantom{\rule{0.3em}{0ex}}\mathrm{GeV}$, in particular what concerns their pseudorapidity dependence. The shape of ${v}_{2}(\ensuremath{\eta})$ is found to be closely related to fast thermalization.