2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/112400QCD penguins are responsible for about 2/3 of the Delta I=1/2 rule in K to pi pi decays, as inferred from a combined analysis of K to pi pi and KL to gamma gamma. Further tests based on the decays KS to pi0 gamma gamma and K+ to pi+ gamma gamma are proposed. New insights into the treatment of pi0, eta, eta' pole amplitudes are also reported.6 pages, 4 figures. Talk given at the 41th Rencontres de Moriond on Electroweak Interactions and Unified Theories, La Thuile, Italy, 11-18 Mar 2006High Energy Physics - Phenomenologytext