Strong Enhancement of ɛ′/ɛ through Final State Interactions

Abstract

We quantify the important effect of strong final state interactions in the weak K→2π amplitudes, using the measured π-π phase shifts with J = 0 and I = 0,2. The final rescattering of the two pions provides a strong enhancement of the ΔI = 1/2 amplitude, which so far has been neglected in the theoretical predictions of ɛ′/ɛ. This correction increases the standard model prediction of ɛ′/ɛ to values in good agreement with the experimental measurements.