Rationale for UV-filtered clover fermions

Abstract

We study the contributions Σ0 and Σ1, proportional to a0 and a1, to the fermion self-energy in Wilson's formulation of lattice QCD with UV-filtering in the fermion action. We derive results for mcrit and the renormalization factors Z S, 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/(Z mZP) 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). © SISSA 2006.