Azimuthal-Angle Dependence of Charged-Pion-Interferometry Measurements with Respect to Second- and Third-Order Event Planes in Au plus Au Collisions at root S-NN=200 GeV

Abstract

Charged-pion-interferometry measurements were made with respect to the second-and third-order event plane for Au + Au collisions at root S-NN = 200 GeV. A strong azimuthal-angle dependence of the extracted Gaussian-source radii was observed with respect to both the second-and third-order event planes. The results for the second-order dependence indicate that the initial eccentricity is reduced during the medium evolution, which is consistent with previous results. In contrast, the results for the third-order dependence indicate that the initial triangular shape is significantly reduced and potentially reversed by the end of the medium evolution, and that the third-order oscillations are largely dominated by the dynamical effects from triangular flow.