Pseudoscalar Meson Dominance and Nucleon Structure

Pseudoscalar meson dominance has implications for nucleon structure which follow from an Extended Partial Conservation of the Axial Current (EPCAC). The minimal resonance saturation of the nucleon pseudoscalar form factor of the lowest pseudoscalar and isovector mesons compatible with pQCD short distance constraints and chiral symmetry. Using PDG masses and widths we obtain gπNN=13.21(-0.06+0.11)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$g_{\pi NN} = 13.21(^{+0.11}_{-0.06})$$\end{document}, to be compared with the most precise determinations from np, pp scattering, gπ+np=13.25(5)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$g_{\pi ^+ np} = 13.25(5)$$\end{document} from the Granada-2013 database. Equivalently a Goldberger–Treiman discrepancy ΔGT=1.8-0.4+0.9%\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Delta _\textrm{GT} = 1.8^{+0.9}_{-0.4}\%$$\end{document} is found. Our results are consistent with almost flat strong pion-nucleon-nucleon vertices.