Energy dependence of heavy-ion initial condition in isobar collisions

Collisions of isobar nuclei, those with the same mass number but different structure parameters, provide a new way to probe the initial condition of the heavy ion collisions. Using transport model simulation of ⁹⁶Ru+⁹⁶Ru and ⁹⁶Zr+⁹⁶Zr collisions at two energies √s_NN = 0.2 TeV and 5.02 TeV, where ⁹⁶Ru and ⁹⁶Zr nuclei have significantly different deformations and radial profiles, we identify sources of eccentricities contributing independently to the final state harmonic flow vn. The efficacy for flow generation is different amount these sources, which qualitatively explains the modest yet significant energy dependence of the isobar ratios of v_n. Experimental measurement of these ratios at the LHC energy and compared with those obtained at RHIC will provide useful insight into the collision-energy dependence of the initial condition.