Weak matrix elements without quark masses on the lattice

We introduce a new parameterization of four-fermion matrix elements which does not involve quark masses and thus allows a reduction of systematic uncertainties in physical amplitudes. As a result the apparent quadratic dependence of epsilon'/epsilon on m(s)(mu) is removed. To simplify the matching between lattice and continuum renormalization schemes, we express our results in terms of Renormalization Group Invariant B-parameters which are renormalization-scheme and scale independent. As an application of our proposal, matrix elements of Delta I = 3/2 and SUSY Delta F = 2 (F = S, C, B) four-fermion operators have been computed.