Determination of the πNN coupling constant in the VPI/GWU πN → πN partial-wave and dispersion relation analysis

Our extraction of the charged pion-nucleon coupling constant from πp elastic scattering data is outlined. A partial wave analysis (Tπ < MeV) is performed simultaneously with a fixed-t dispersion relation (DR) analysis (< 800 MeV). The πNN coupling constant g2/4π and other DR parameters are searched to find the best fit. The result 13.73 ±0.01 ±0.07 (first error statistical, second systematic) is found to be insensitive to database changes and Coulomb barrier corrections. This value satisfies important elements of low energy QCD like the Goldberger-Treiman discrepancy, the Dashen-Weinstein sum rule, and chiral predictions of threshold pion photoproduction.