The scattering of p-wave positrons by helium

Abstract

Kohn's variational method is used to calculate low energy positron-helium p-wave phaseshifts and p-wave contributions to the annihilation rate parameter Zeff for the two helium models considered previously by Humberston (1973). The phaseshifts for both models are less positive than the lowest set of Drachman, but the cross sections and annihilation rates obtained from the present results and Humberston's s-wave results, for the more elaborate helium function, are in good agreement with the experimental values of Canter et al. (1973) and Coleman et al.