On the $\eta$ and f${}_1$(1420) Couplings to the Nucleon

Abstract

We consider neutral pseudoscalar, $\eta$, and axial vector, $f_1(1420)$, mesons in the OZI-rule-respecting flavor basis, $\{(\bar{s}s),\frac{1}{\sqrt{2}}(\bar{u}u+\bar{d}d)\}$, and suggest a scenario for their coupling to the nucleon. Within this framework, the non--strange parts of the $\eta N$ and f${}_{1}N$ couplings are modeled by means of triangular $a_0\pi N$, and $K{K}^{\ast }(\Lambda /\Sigma )$ vertices, while the strange ones partly proceed via Goldberger-Treiman relations, which have been concluded solely on the grounds of current universality. The suggested model explains the observed suppression of the $\eta N$ coupling with respect to the constituent quark model expectations, and predicts the coupling of $f_1$ to the nucleon.

Comments: appears in Int. J. Mod. Phys. A (in press)