Non-perturbative renormalization of lattice four-fermion operators withoutpower subtractions

A general nonperturbative analysis of the renormalization properties of Del ta I = 3/2 four-fermion operators in the framework of lattice regularizatio n with Wilson fermions is presented. We discuss the nonperturbative determi nation of the operator renormalization constants in the lattice regularizat ion independent (RI or MOM) scheme. We also discuss the determination of th e finite lattice subtraction coefficients from Ward identities. We prove th at, at large external virtualities, the determination of the lattice mixing coefficients, obtained using the RI renormalization scheme, is equivalent to that based on Ward identities, in the continuum and chiral limits. As a feasibility study of our method, we compute the mixing matrix at several re normalization scales, for three Values of the lattice coupling beta, using the Wilson and tree-level improved SW-Clover actions.