THE DELTA-S=1 WEAK CHIRAL LAGRANGIAN AS THE EFFECTIVE THEORY OF THE CHIRAL QUARK-MODEL

We use the chiral quark model to construct the complete O(p(2)) weak D elta S = 1 chiral lagrangian via the bosonization of the ten relevant operators of the effective quark lagrangian. The chiral coefficients a re given in terms of f(pi), the quark and gluon condensates and the sc ale-dependent NLO Wilson coefficients of the corresponding operators; in addition, they depend on the constituent quark mass M, a parameter characteristic of the model, All contributions of order N-c(2) as well as N-c and alpha(s)N(c) are included. The gamma(5)-scheme dependence of the chiral coefficients, computed via dimensional regularization, a nd the Fierz transformation properties of the operator basis are discu ssed in detail. We apply our results to the evaluation of the hadronic matrix elements for the decays K --> 2 pi, consistently including the renormalization induced by the meson loops. The effect of this renorm alization is sizable and introduces a long-distance scale dependence t hat matches in the physical amplitudes the short-distance scale depend ence of the Wilson coefficients.