Chiral symmetry tests in nonleptonic K decay

Strong enhancement of varepsilon(')/varepsilon through final state interactions

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