EUROPEAN PHYSICAL JOURNAL A, vol.52, no.4, pp.1-9, 2016 (SCI-Expanded)
We study the strong vertices N*N pi, N*N*pi and NN pi in QCD, where N* denotes the negative-parity N(1535) state. We use the most general form of the interpolating currents to calculate the corresponding strong coupling constants. It is obtained that the coupling associated to N*N pi vertex is strongly suppressed compared to those related to two other vertices. The strong coupling corresponding to N*N*pi is obtained to be roughly half of that of NN pi vertex. We compare the obtained results on N*N pi and NN pi vertices with the existing predictions of other theoretical studies as well as those extracted from the experimental data.