Phenomenological aspects of isospin violation in the nuclear force

Phenomenological Lagrangians and dimensional power counting are used to assess isospin violation in the nucleon-nucleon force. The πNN coupling constants (including the Goldberger-Treiman discrepancy), charge-symmetry breaking, and meson-mixing models are examined. A one-loop analysis of the isospin-violating πNN coupling constants is performed using chiral perturbation theory. Meson-mixing models and the 3He3H mass difference are also discussed in the context of naturalness.