Beam-energy and collision-system dependence of the linear and mode-coupled flow harmonics from STAR
Abstract
Recent measurements and hydrodynamic model calculations suggest that the higher-order flow coefficients v4 and v5 have two contributions: a linear contribution driven by the initial-state eccentricities, n, and a mode-coupled contribution derived from the lower-order eccentricity coefficients 2 and 3. Measurements of these two contributions to v4 and v5 provide crucial insights to discern initial-state models and to constrain the temperature-dependent specific shear viscosity, η/s, of the plasma produced in heavy-ion collisions. In this work, we have employed the two-subevents cumulant technique to provide the first beam-energy and collision-system dependence of the linear and mode-coupled contributions to the higher-order flow harmonics. Our results are shown and discussed for several centrality intervals for U+U collisions at sNN= 193 GeV, Au+Au collisions at sNN=200, and 54.4 GeV and Cu+Au collisions at sNN=200 GeV. The results are compared with similar studies performed by the ALICE experiment at LHC.