Topological charge renormalization: A test case for 3-loop vacuum calculations using overlap fermions and Symanzik improved gluons

Abstract

We calculate perturbative renormalization properties of the topological charge, using the standard lattice discretization given by a product of twisted plaquettes. We use the overlap and clover action for fermions, and the Symanzik improved gluon action for 4- and 6-link loops. We compute the multiplicative renormalization of the topological charge density to one loop; this involves only the gluon part of the action. The power divergent additive renormalization of the topological susceptibility is calculated to 3 loops.

6 pages, 5 figures, poster presented at Lattice2005(renormalization and improvement), Dublin, July 25-30, 2005. A longer write-up may be found in hep-lat/0509012