Beam-energy and collision-system dependence of the linear and mode-coupled flow harmonics from STAR

Recent measurements and hydrodynamic model calculations suggest that the higher-order flow coefficients ν₄ and ν₅ have two contributions: a linear contribution driven by the initial-state eccentricities, ε_n, and a mode-coupled contribution derived from the lower-order eccentricity coefficients ε₂ and ε₃. Measurements of these two contributions to ν₄ and ν₅ 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 $\sqrt{s_{NN}}=193\text{GeV}$, Au+Au collisions at $\sqrt{s_{NN}}=200,\text{and}54.4\text{GeV}$ and Cu+Au collisions at $\sqrt{s_{NN}}=200\text{GeV}$. The results are compared with similar studies performed by the ALICE experiment at LHC.