2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/49687A calculation of the hadronic matrix elements for K\toππincluding π-πrescattering effects in a dispersion integral is presented. I study the dependence of the results on the matching scale μand use them to calculate the CP-parameter (ε\prime/ε). I find improved stability on the matching scale and good agreement with the experimental results.11 pages, one additional remark, citations correctedHigh Energy Physics - Phenomenologytext