Neutral Pion Production In Proton Proton Collisions Close To The Kinematical Threshold PDF Download

We showed that the threshold production of [pi]°pp, [pi]np, and [pi]d from proton-proton collisions can be consistently described by a model consisting of pion s-wave rescattering and N{bar N} pair-terms of heavy-meson exchanges. The large difference between [sigma]{sup tot}(pp 2![pi]d) and [sigma]{sup tot}(pp 2![pi]+np) is understood from the orthogonality of the deuteron and the np scattering wave functions. In a calculation using the Paris potential, we find that the data can be reproduced best by using a soft [pi]NN form factor with [Delta] = 650 MeV for a monopole form. This is consistent with our earlier studies of pion production in the A-excitation region. A paper describing this result was submitted for publication.