The reaction pp → ppπ0 near threshold

We perform a momentum-space calculation of the reaction pp → ppπ0 near threshold. Direct production and pion rescattering are taken into account. For the latter a T-matrix obtained from a microscopic model of the πN interaction is employed. The effects of some approximations commonly used in studies of pp → ppπ0 are discussed. We find that those approximations overestimate the cross section and also modify its energy dependence. We obtain a significant contribution from rescattering, but not nearly enough to describe the data.