Determination of the NNπ coupling constants in NN partial-wave analyses

The NNπ coupling constants are extracted in NN partial-wave analyses. The data base contains all pp and np scattering data below Tlab=350 MeV. Introducing different coupling constants at the different NNπ vertices, at the pion pole we find for the ppπ0 coupling fp2=0.0751(6), for the nnπ0 coupling fn2=0.075(2), and for the charged-pion coupling fc2=0.0741(5). These results allow only small charge-independence-breaking effects in the NNπ coupling constants. If we assume charge independence, we find f2=0.0749(4). The value found for fc2 is in agreement with the determination in a recent VPI ampersand SU analysis of the πN scattering data, and with its determination in an analysis of the charge-exchange reaction bar pp→ bar nn