Positronium-formation cross sections in the eikonal approximation

Positronium formation cross sections have been studied in the framework of the eikonal approximation, where the boundary condition has been properly satisfied, taking consistent account of the internuclear potential term both in the eikonal phase and in the interaction potential. The six-dimensional integral of the Glauber eikonal amplitude has been reduced to a single-dimensional one. The differential as well as the total cross sections have been studied and compared with other existing theoretical results, as the experimental data are not yet available in the literature. The eikonal results are found to give reasonable estimates at intermediate, high and extremely high energies. (16 refs., 3 tabs., 5 figs.)