#### Abstract

We study the contributions Σ0 and Σ1, proportional to a 0 and a1, to the fermion selfenergy in Wilson’s formulation of lattice QCD with UV-filtering in the fermion action. We derive results for mcrit and the renormalization factors ZS , ZP , ZV , ZA to 1-loop order in perturbation theory for several filtering recipes (APE, HYP, EXP, HEX), both with and without a clover term. The perturbative series is much better behaved with filtering, in particular tadpole resummation proves irrelevant. Our non-perturbative data for mcrit and ZA/(ZmZP ) show that the combination of filtering and clover improvement efficiently reduces the amount of chiral symmetry breaking – we find residual masses amres = O(10 −2).