On the strong coupling $N^{(\ast )}{N}^{(\ast )}\pi$

Abstract

We study the strong vertices $N^{\ast }N\pi$, $N^{\ast }{N}^{\ast }\pi$ and $NN\pi$ in QCD, where $N^{\ast }$ 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 $N^{\ast }N\pi$ vertex is strongly suppressed compared to those related to two other vertices. The strong coupling corresponding to $N^{\ast }{N}^{\ast }\pi$ is obtained to be roughly half of that of $NN\pi$ vertex. We compare the obtained results on $N^{\ast }N\pi$ and $NN\pi$ vertices with the existing predictions of other theoretical studies as well as those extracted from the experimental data.

Comments: 15 Pages, 4 Figures and 3 Tables