Matching the Electroweak Penquins Q_7 and Q_8

Abstract

We report on recent advances on the computation of the matrix elements of the electroweak penguins Q_7 and Q_8 which are relevant for the Delta I=3/2 contribution to epsilon'_K in the chiral limit. The matching of scale and scheme dependences between Wilson coefficients and these matrix elements is done analytically at NLO in alpha_S.

Comments: Invited talk given by J.P. at XIV Rencontres de Blois, "Matter Anti-Matter Asymmetry", 18-24 June 2002, and by E.G. at QCD 2002, Montpellier, 2-9 July 2002