Eur. Phys. J. A (2011) 47: 12
https://doi.org/10.1140/epja/i2011-11012-9

Regular Article - Theoretical Physics

Chiral perturbation theory calculation for pn d at threshold

¹ School of Science, Xian Jiaotong University, 710049, Xian, China
² Institut für Kernphysik and Jülich Center for Hadron Physics, Forschungszentrum Jülich, D-52425, Jülich, Germany
³ Institute for Theoretical and Experimental Physics, B. Cheremushkinskaya 25, 117218, Moscow, Russia
⁴ Institute for Advanced Simulation, Forschungszentrum Jülich, D-52425, Jülich, Germany

^* e-mail: v.baru@fz-juelich.de

Received: 21 July 2010
Accepted: 6 December 2010
Published online: 24 January 2011

Abstract

We investigate the reaction pn d in the framework of Chiral Perturbation Theory (ChPT). For the first time a complete calculation of the leading-order contributions is presented. We identify various diagrams that are of equal importance as compared to those recognized in earlier works. The diagrams at leading order behave as expected by the power counting. Also for the first time the nucleon-nucleon interaction in the initial, intermediate and final state is included consistently and found to be very important. Although the perturbative series for the production operator is expected to converge very slowly, this study provides the theoretical basis for a future evaluation of the non-resonant contributions in two-pion production reactions in nucleon-nucleon collisions.