Study of the Pion-Nucleon Coupling Constant Charge Dependence on the   Basis of the Low-Energy Data on Nucleon-Nucleon Interaction
  We study relationship between the physical quantities that characterize pion-nucleon and nucleon-nucleon interaction on the basis of the fact that nuclear forces in the nucleon-nucleon system at low energies are mainly determined by the one-pion exchange mechanism. By making use of the recommended proton-proton low-energy scattering parameters, we obtain the following value for the charged pion-nucleon coupling constant g$_{\pi ^{\pm }}^{2}/4\pi =14.55(13)$. Calculated value of this quantity is in excellent agreement with the experimental result g$_{\pi ^{\pm }}^{2}/4\pi =14.52(26)$ of the Uppsala Neutron Research Group. At the same time, the obtained value of the charged pion-nucleon coupling constant differs markedly from the value of the neutral pion-nucleon coupling constant g$_{\pi ^{0}}^{2}/4\pi =13.55(13)$. Thus, our results show considerable charge splitting of the pion-nucleon coupling constant. 
V. A. Babenko, N. M. Petrov
nucl-th hep-ph