Talk presented by Claude Bernard

Parallel Session: Improvement and Renormalization II

Tuesday June 29th, 16.40 - 17.00, Room B

Authors: The work described is done in collaboration with Thomas DeGrand.

Perturbation Theory for Fat-link Fermion Actions

Abstract: Smearing or "fattening'' the gauge links in a fermion action has several advantages. Indeed, with sufficient fattening, the scaling properties are improved and exceptional configurations are suppressed. Here, we discuss weak coupling perturbation theory for such actions. The normally large integrals that appear in lattice perturbation theory (including both lattice tadpoles and other UV dominated contributions) are drastically reduced. Further, even without detailed calculation, it is easy to determine to good accuracy the scale of the logarithms that appear in cases where an anomalous dimension is present. We describe several one-loop examples for fat-link Wilson and Clover fermions. These examples will be taken from the following list: the shift in $\kappa_c$, the relation between the lattice and $\overline{MS}$ quark masses, and the axial current renormalization factor ($Z_A$) for light-light and static-light currents.

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