Positron–hydrogen scattering by the Faddeev approach

An approximate form of the Faddeev equations has been employed to investigate the e+–H scattering problem with the inclusion of the couplings of the 1s, 2s, and 2p states of the hydrogen atom and the ground state of the Ps atom. As no experimental measurements have been reported until now, the present predictions with and without the inclusion of the Ps formation have been compared with other existing theoretical findings. In the low energy region the effects of the Ps-formation channel on the elastic cross sections have been found to be quite important. The present values for the Ps-formation cross section are slightly smaller than the FBA results. The results for 1s–2s and 1s–2p excitations are seen to be influenced considerably in the low energy region by the inclusion of the Ps-formation channel whereas from E?150 eV these results are very close to the corresponding FBA values.