Elliptic flow measurements from two-, four- and six-particle correlations are used to investigate flow fluctuations in collisions of U+U at $\sqrt{ s_{ \rm NN}}$= 193 GeV, Cu+Au at $\sqrt{ s_{ \rm NN}}$= 200 GeV and Au+Au spanning the range $\sqrt{ s_{ \rm NN}}$= 11.5 - 200 GeV. The measurements show a strong dependence of the flow fluctuations on collision centrality, a modest dependence on system size, and very little if any, dependence on particle species and beam energy. The results, when compared to similar LHC measurements, viscous hydrodynamic calculations, and T$\mathrel{ \protect\raisebox{ -2.1pt}{ R}}$ENTo model eccentricities, indicate that initial-state-driven fluctuations predominate the flow fluctuations generated in the collisions studied.
Categories: nucl-ex