Ma. Samuel, VERTICAL-BAR-DELTA-I-VERTICAL-BAR=1 2 RULE IN THE STANDARD MODEL/, International journal of theoretical physics, 35(7), 1996, pp. 1389-1392
We consider the K --> pi pi amplitudes in the Standard Model. We show
that the infamous \Delta I\ = 1/2 rule can be explained by using Fade
approximants to sum the diverging QCD perturbation series.