Sala Seminarios IFIC (Edf. Institutos de Investigación)
Sala Seminarios IFIC
Edf. Institutos de Investigación
Descripción
Exact analytical expressions for the Delta S=1 coupling Im(G_E) in terns of observable spectral functions are given. This coupling determines the size of the Delta I =3/2 contributions to epsilon '. We show how the scheme- and scale dependences vanish to all orders in 1/N_c and NLO in alpha_S explicitly both for Q_7 and Q_8. Numerical results are derived for both Q_7 and Q_8 from the tau-data and known results on scalar spectral functions. In particular, we study the effect of all higher dimensional operators. The coefficients of the leading operators in the OPE of the needed correlators are derived to NLO in alpha_s.