https://doi.org/10.1140/epja/i2006-10002-4
Nuclear Structure and Reactions
Towards a field theoretic understanding of NN → NNπ
1
Institut für Kernphysik, Forschungszentrum Jülich GmbH, D-52425, Jülich, Germany
2
Institute of Theoretical and Experimental Physics, B. Cheremushkinskaya 25, 117259, Moscow, Russia
3
Helmholtz-Institut für Strahlen- und Kernphysik (Theorie), Universität Bonn, Nußallee 14-16, D-53115, Bonn, Germany
* e-mail: c.hanhart@fz-juelich.de
Received:
7
February
2006
Accepted:
7
February
2006
Published online:
21
February
2006
We study the production amplitude for the reaction NN → NNπ up to next-to-leading order in chiral perturbation theory using a counting scheme that takes into account the large scale introduced by the initial momentum. In particular, we investigate a subtlety that arises once the leading loop contributions are convoluted with the NN wave functions as demanded by the non-perturbative nature of the NN interaction. We show how to properly identify the irreducible contribution of loop diagrams in such type of reaction. 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, bringing its contribution to the cross-section for pp → dπ+ close to the experimental value.
PACS: 21.30.Fe Forces in hadronic systems and effective interactions – / 12.39.Fe Chiral Lagrangians – / 25.10.+s Nuclear reactions involving few-nucleon systems – / 25.40.Ve Other reactions above meson production thresholds (energies > 400MeV) –
© Società Italiana di Fisica and Springer-Verlag, 2006