Attenuation of the singlet quark--anti-quark bound state passing through a random external SU(N) color field at high energy is studied within the eikonal framework as a model for the absorption of a quarkonium by nuclear target. For a thick target of length L the penetration probability is suppressed non-exponentially and behaves asymptotically $\propto 1/LN^2$ with 1/N^2 indicating the equi-partitioning in the color space. An approximate rational expression for the penetration of the small Gaussian bound state is found which allows the explicit L and N dependences, and shows the attenuation is in the powers of L although the approach to the asymptote is rather slow.
Categories: nucl-th hep-ph