Advances in the field-theoretic understanding of pion production in nucleon-nucleon collisions

Lensky, V.; Haidenbauer, J.; Hanhart, C.; Baru, V.; Kudryavtsev, A.; Meißner, U. -G.

Advances in the field-theoretic understanding of pion production in nucleon-nucleon collisions

Authors

Description

We study the production amplitude for the reaction $NN\to NNπ$ up to next-to-leading order in chiral perturbation theory. We show that the irreducible chiral loops at this order exactly cancel those terms that arise from the off-shell parts of the $πN$ rescattering vertex. This cancellation is required for formal consistency of the whole scheme. The net effect of the inclusion of all next-to-leading order loops is to enhance the leading rescattering amplitude by a factor of 4/3 compared to phenomenological studies, bringing its contribution to the cross section for $pp\to dπ^+$ close to the experimental value.
To appear in the proceedings of the international conference MESON 2006, Cracow, Poland, 9 - 13 June 2006; 4 pages, 2 figures, uses ws-ijmpa.cls