Positron-hydrogen scattering below the first excitation threshold

A five-state (H(1s, 2s, 2p, 3d), Ps(1s)) CCA has been employed to study positron-hydrogen scattering in the energy range k=0.1 to 0.85 au. The elastic d-wave phaseshifts are found to be in excellent agreement with those of existing reliable predictions. The effect of the positronium formation channel is found to be significant. The differential and total cross sections are reported by combining the present CCA results (l)2) and nearly exact numbers obtained using variational methods.