Chiral Unitary Approach To The N*N*pi, N*N*eta Couplings For The N*(1535) Resonance

Abstract

Using a chiral unitary model in which the negative parity nucleon resonance $N^{\ast }\equiv N^{\ast }(1535)$ is generated dynamically by means of the Bethe Salpeter equation with coupled meson baryon channels in the $S=0$ sector, we have obtained the ${\pi }^0{N}^{\ast }{N}^{\ast }$ and $\eta N^{\ast }{N}^{\ast }$ couplings. The ${\pi }^0{N}^{\ast }{N}^{\ast }$ coupling has smaller strength and the same sign as the ${\pi }^{0}NN$ coupling. This rules out the mirror assignment of chiral symmetry where the ground state nucleon $N$ and the negative parity resonance $N^{\ast }$ are envisaged as chiral partners in the baryon sector.

Comments: 30 pages, 15 figures (ps files). The new version discusses pi-N scattering around the N*(1535) resonance