How Sensitive Are Various N N Observables to Changes in the Πn N Coupling Constant?

The deuteron, N N analyzing powers A y , and the singlet scattering length show great sensitivity to the πN N coupling constant g π. While the pp A y data favor g 2 π /4π ≤ 13.6, the np A y data and the deuteron quadrupole moment imply g 2 π /4π ≥ 14.0. The two diverging values could be reconciled by the assumption of (substantial) charge-splitting of g π. However, the established theoretical explanation of the charge-dependence of the 1 S 0 scattering length (based upon pion mass splitting) is very sensitive to a difference between g π 0 and g π ± and rules out any substantial charge-splitting of g π. Thus, there are real and large discrepancies between the values for g π extracted from different N N observables. Future work that could resolve the problems is suggested.