Reaction plane angle dependence of dihadron azimuthal correlations from a multiphase transport model calculation

Dihadron azimuthal angle correlations relative to the reaction plane have been investigated in Au+Au collisions at s(NN)=200 GeV using a multiphase transport model (AMPT). Such reaction plane azimuthal-angle-dependent correlations can shed light on the path-length effect of energy loss of high-transverse-momentum particles propagating through a hot dense medium. The correlations vary with the trigger particle azimuthal angle with respect to the reaction plane direction, phi(s)=phi(T)-Psi(EP), which is consistent with the experimental observation by the STAR Collaboration. The dihadron azimuthal angle correlation functions on the away side of the trigger particle present a distinct evolution from a single-peak to a broad, possibly double-peak structure when the trigger particle direction goes from in-plane to out-of-plane with the reaction plane. The away-side angular correlation functions are asymmetric with respect to the back-to-back direction in some regions of phi(s), which could provide insight into the testing v(1) method for reconstructing the reaction plane. In addition, both the root-mean-square width (W-rms) of the away-side correlation distribution and the splitting parameter (D) between the away-side double peaks increase slightly with phi(s), and the average transverse momentum of away-side-associated hadrons shows a strong phi(s) dependence. Our results indicate that a strong parton cascade and resultant energy loss could play an important role in the appearance of a double-peak structure in the dihadron azimuthal angular correlation function on the away side of the trigger particle.