π B₈B₈ and σ B₈B₈ couplings from a chiral quark potential model

From an SU(2)$\otimes $SU(2) chiral quark potential model incorporating spontaneous chiral symmetry breaking the asymptotic $\pi $ and $\sigma $ exchange pieces of the $NN$ potential are generated. From them the $\pi NN$ and $\sigma NN$ coupling constants can be extracted. The generalization to SU(3)$\otimes $SU(3) allows for a determination of $\pi B_{8}B_{8}$ and $% \sigma B_{8}B_{8}$ coupling constants according to exact SU(3) hadron symmetry. The implementation of the values of the couplings at $Q^{2}=0$ provided by QCD sum rules and/or phenomenology makes also feasible the extraction of the meson-baryon-baryon form factors. In this manner a quite complete knowledge of the couplings may be attained.