The First Moment of Azimuthal Anisotropy in Nuclear Collisions from AGS to LHC Energies

Figure 13

Beam energy dependence of directed flow slope for protons in 10–40% centrality Au+Au from the STAR experiment, compared with recent available model calculations [19, 20, 94]. All the experimental data are from [47] except for one energy point, GeV [90], which should be considered a preliminary measurement. The Frankfurt hybrid model [95] and a pure hydro calculation with particle freeze-out at constant energy density [95] both lie above the data and are off-scale at all BES energies.