Speaker
Description
Studies of longitudinal decorrelation of anisotropic flow provide unique constraints on the initial conditions and dynamical evolution of the quark- gluon-plasma in heavy-ion collisions. With data collected by the STAR experiment at RHIC, the factorization ratio for flow harmonics, rn(η, ηref )(n = 2,3), are obtained over a wide η range for 27, 54.4 and 200 GeV Au+Au collisions as a function of centrality. We observe a clear collision energy dependence indicating a stronger longitudinal decorrelation at lower collision energies. The 4-particle correlator (Rn(η, ηref )(n = 2, 3)) used to separate the event-plane twist from vn magnitude fluctuations, will also be presented. The results provide new insights into the three-dimensional modeling of the initial stage and the evolution of relativistic heavy-ion collisions, especially their collision energy dependence.
