Nuclear A-dependence near the Saturation Boundary

Abstract

The A-dependence of the saturation momentum and the scaling behavior of the scattering of a small dipole on a nuclear target are studied in the McLerran-Venugopalan model, in fixed coupling BFKL dynamics and in running coupling BFKL dynamics. In each case, we find scaling not too far from the saturation boundary, although for fixed coupling evolution the scaling function for large A is not the same as for an elementary dipole. We find that $Q_s^2$ is proportional to $A^{1/3}$ in the McLerran-Venugopalan model and in fixed coupling evolution, however, we find an almost total lack of A-dependence in $Q_s^2$ in the case of running coupling evolution.