| ΔS| = 1 non-leptonic amplitudes and the 1/ Nc expansion

Abstract

The application of the 1/ N c expansion to the estimate of weak non-leptonic amplitudes is studied. The formulation is renormalization-group invariant and consistent with chiral symmetry. The problem of matching the short- and long-distance descriptions is properly displayed and evidence is shown for the need of more information beyond that known in these regimes. The matching problem first appears at O(1/ N c), but is important because in the 1/ N c approach the relevant octet enhancement (Δ1 = 1 2 rule) requires large contributions from these O(1/ N c) terms.