Differential cross section for positronium formation in positron-atomic-hydrogen collisions

We have combined the $L=0\mathrm{} \mathrm{and} 1$ partial-wave amplitudes obtained by a two-state coupled static approximation with correlation with the $L\ge 2$ Born amplitudes to obtain the differential cross section for positronium formation in positron-atomic-hydrogen collisions. For positron energies of 0.64 and 0.75 Ry, minima at the scattering angles of 57° and 51° are found. Total cross sections for positronium formation for low and intermediate impact energies are given. Measurement of the differential cross section for the process $e^{+}+\mathrm{He}\to \mathrm{Ps}+{\mathrm{He}}^{+}$ for the detection of possible minima is suggested.