Figure 3: Subtracted Sivers function for the up quarks in Drell-Yan in -space (upper panels) and -space (lower panels), at energies: (solid lines), (dashed lines), and (dotted lines). The left panel shows the result from the same evolution kernel as that for in (66); the right panel shows the result from an approximate evolution kernel for the Qiu-Sterman function in (65), respectively. Figure from [60].