THEORETICAL STUDY OF THE NN → NNππ REACTION

Abstract

We have developed a model for the NN → NNππ reaction and evaluated cross sections for the different charged channels. The low energy part of those channels where the pions can be in an isospin zero state is dominated by N ∗ excitation, driven by an isoscalar source recently found experimentally, followed. At higher energies, and in channels where the pions are not in T=0, ∆ excitation mechanisms become relevant. A rough agreement with the experimental data is obtained in most channels. Repercussions of the present findings for the ABC effect and the pp → ppπ0 reaction close to threshold are also suggested. by the decay N ∗ → N(ππ) T=0 S−wave 1 1 Introduction. Pion production in NN collisions is one of the sources of information on the NN interaction and about nucleon resonance properties. Particularly the two pion production channel might be especially enlightening in view of the interesting information