A characteristic feature of small-x lepton-proton data from HERA is geometric
scaling -- the fact that over a wide range of x and Q^2 all data can be
described by a single variable Q2/Qsat2(x), with all x-dependence
encoded in the so-called saturation momentum Qsat(x). Here, we observe
that the same scaling ansatz accounts for nuclear photoabsorption cross
sections and favors the nuclear dependence Qsat,A2∝AαQsat2, α≃4/9. We then make the empirical finding
that the same A-dependence accounts for the centrality evolution of the
multiplicities measured in Au+Au collisions at RHIC. It also allows to
parametrize the high-p_t particle suppression in d+Au collisions at forward
rapidities. If these geometric scaling properties have a common dynamical
origin, then this A-dependence of Qsat,A2 should emerge as a consequence
of the underlying dynamical model.Comment: 4 pages, 3 postscript figure