Trace initial interaction from final state observable in relativistic heavy ion collisions

In order to trace the initial interaction in ultra-relativistic heavy ion collision in all azimuthal directions, neighboring angular-bin multiplicity correlation pattern is suggested. From the simulation of Au+Au collisions at \(\sqrt {s_{NN} } \) = 200 GeV by using the Monte Carlo models RQMD with hadron re-scattering and AMPT with and without string melting, we observe that the correlation pattern changes gradually from out-of-plane preferential one to inplane preferential one when the centrality of collision shifts from central to peripheral. This regularity is found to be model and collision energy independent. The physics behind the two opposite trends of correlation pattern is discussed.