Coupled channels approach to eta N and eta ' N interactions

摘要

We present a coupled channels separable potential approach to eta N and eta'N interactions using a chiral symmetric interaction kernel. The s-wave pi N amplitudes and pi(-) p induced total cross sections are reproduced satisfactorily in a broad interval of energies despite limiting the channel space to two-body interactions of pseudoscalar mesons with the baryon ground-state octet. It is demonstrated that an explicit inclusion of the eta 0 meson singlet field leads to a more attractive eta N interaction, with the real part of the scattering length exceeding 1 fm. The eta'N diagonal coupling appears sufficient to generate an eta'N bound state but the inter-channel dynamics moves the respective pole far from the physical region making the eta'N interaction repulsive at energies around the channel threshold. The N* (1535) and N* (1650) resonances are generated dynamically and the origin and properties of the S-matrix poles assigned to them are studied in detail. We also hint at a chance that the N* (1895) state might also be formed provided a suitably varied model setting is found. (C) 2019 Elsevier B.Y. All rights reserved.