Dihadron Correlations Relative to the Event Plane in 200 GeV Au+Au Collisions from STAR

Abstract

Dihadron correlations with a high-pt trigger particle are analyzed by STAR relative to the event plane in Au+Au collisions at 200 GeV (arXiv:1010.0690v1). The elliptic and quadrangular flow anisotropies are subtracted. The remaining dihadron correlation signals are found to be composed of a near-side peak, which is separated into jet-like and "ridge"-like components, and an away-side correlation structure. The ridge-like structure is found to decrease with the trigger particle azimuthal angle relative to the event plane from in-plane to out-of-plane. The away-side structure is found to evolve from single-peak for in-plane triggers to double-peak for out-of-plane triggers. Is the dihadron correlation signal just a manifestation of the triangular and higher-order harmonic flows? This talk addresses this question, exploring the answers using limiting-case assumptions, and discusses the implications of the data regarding the ridge and the double-peak structure.