NONPERTURBATIVE IMPROVEMENT AND RENORMALIZATION OF LATTICE OPERATORS

The Alpha Collaboration has proposed an optimal value for c(sw) in the Sheikholeslami-Wohlert action, chosen to remove O(a) effects. To meas ure hadronic matrix elements to the same accuracy we need a method of finding O(a) improved operators, and their renormalization constants. We determine the Z factors by a non-perturbative method, measuring the matrix elements for single quark states propagating through gauge fie lds in the Landau gauge. The data show large effects coming from chira l symmetry breaking. This allows us to find the improvement coefficien ts too, by requiring that the amount of chiral symmetry breaking agree s with that predicted by the chiral Ward identities.