Physics Below 1-GeV

Constraints on physics beyond the standard model require a preliminary understanding of the interplay between the electroweak and strong interactions. Strong interaction effects are in principle non-negligible below the confining scale. A complementary approach based on the meson-quark duality and applied on the π+ − π0> electromagnetic mass difference and the weak K-decays confirms this expectation. Using this simple non-perturbative framework, we conclude that both the empirical Image rule and the recently measured ε′/ε are consistent with the standard model.