Initial-state Coulomb interaction in the dd→απ⁰ reaction

The effects of initial-state Coulomb interactions in the charge-symmetry-breaking reaction dd→απ⁰ are investigated within a previously published formalism. This is a leading order effect in which the Coulomb interaction between the two initial state protons leads to the breakup of the two deuterons into a continuum state that is well connected to the final απ⁰ state by the strong emission of a pion. As a first step, we use a simplified set of d and α wave functions and a plane-wave approximation for the initial dd state. This Coulomb mechanism, by itself, yields cross sections that are much larger than the experimental ones, and which are comparable in size to the contributions from other mechanisms. Inclusion of this mechanism is therefore necessary in a realistic calculation.