We test the recent proposal of using the Ward identities to compute the K-0 - (K) over bar (0) mixing amplitude with Wilson fermions, without the problem of spurious lattice subtractions. From our simulations, we observe no difference between results obtained with and without subtractions. From the standard study of the complete set of DeltaS = 2 operators, we quote the following (preliminary) results: B-K((MS) over bar) (2 GeV) = 0.70(10), (O-tau)(K-->pipi)((I=2)) = 0.10(2)(1)GeV3, <O-8>((I=2))(K-->pipi) = 0.49(6)(0)GeV3.
Becirevic, D., Boucaud, P., Gimenez, V., Lubicz, V., Martinelli, G., Papinutto, M. (2002). Matrix elements of Delta S=2 operators with Wilson fermions. In LATTICE 2001. Proceedings of the XIXth International Symposium on Lattice Field Theory (pp.326-328) [10.1016/S0920-5632(01)01703-0].