The Goldberger–Treiman discrepancy in SU(3)

The Goldberger–Treiman discrepancy in SU(3) is analyzed in the framework of heavy baryon chiral perturbation theory (HBChPT). It is shown that the discrepancy at leading order is entirely given by counterterms from the O(p3) Lagrangian, and that the first subleading corrections are suppressed by two powers in the HBChPT expansion. These subleading corrections include meson-loop contributions as well as counterterms from the O(p5) Lagrangian. Some one-loop contributions are calculated and found to be small. Using the three discrepancies (πNN, KNΛ and KNΣ) which can be extracted from existing experimental data, we find that the HBChPT calculation favors the smaller gπNN values obtained in recent partial wave analyses.