Exploring the initial state in relativistic heavy ion collisions

While the most spectacular effects seen in relativistic heavy ion collisions are attributed to the formation of a strongly interacting, hot and dense medium (final state), there is a rapidly growing consensus that the initial state of the incoming relativistic nuclei is in part responsible for the observed phenomena. The initial state is best studied in d+Au collisions where only cold nuclear matter is present and probed by a single proton or neutron. Based on the latest results from the PHENIX experiment at RHIC (BNL) from the high statistics d+Au data at root sNN-200 GeV (2008) we will review the nuclear modification factors at forward rapidities as well as the status of central-forward and forward-forward correlations which provide an important test of gluon saturation in the Au nucleus at low momentum fraction x.