Nucleus-nucleus scattering in perturbative QCD with $N_c\to \mathrm{\infty }$

In the perturbative QCD with $N_c\to \mathrm{\infty }$ equations for the amplitude of the nucleus-nucleus scattering are derived by the effective field method. The asymptotic form of the solution is discussed. It is argued that in the high-energy limit the total nucleus-nucleus cross-sections become constant and purely geometrical.