CHIRAL CORRECTIONS TO THE K(0)-(K)OVER-BAR-(0) B-K-PARAMETER

I study the chiral corrections to the O(p(2)) prediction of Chiral Perturbation Theory B-K similar or equal to 0.29. I point out that neglecting non-factorizable chiral corrections one obtains B-K similar or equal to 0.61; this result takes into account factorizable chiral corrections to all orders in the chiral expansion. Non-factorizable O(p(4)) chiral corrections are computed within the framework of the mean field approximation of the Extended Nambu-Jona-Lasinio Model and appear to be negative. I find B-K = 0.38(-0.02)(+0.10).