Delta I=1/2 enhancement and the Glashow-Schnitzer-Weinberg sum rule

In 1967 Glashow, Schnitzer and Weinberg derived a sum rule in the soft-pion and soft kaon limit relating the Delta I= 1/2 non-leptonic K --> 2 pi ampl itude to integrals over strange and non-strange spectral functions. Using t he recent ALEPH data from tau-decay, we show that the sum rule, slightly mo dified to reduce contributions near the cut, yields the correct magnitude d ecay amplitude corresponding to the Delta I = 1/2 rule. (C) 2000 Elsevier S cience B.V. All rights reserved.