Center vortex model for the infrared sector of Yang-Mills theory - topological susceptibility

A definition of the Pontryagin index for SU(2) center vortex world-surfaces composed of plaquettes on a hypercubic Lattice is constructed. It is used to evaluate the topological susceptibility In a previously defined random surface model for vortices, the parameters of which have been fixed such as to reproduce the confinement properties of SU(2) Yang-Mills theory. A prediction for the topological susceptibility is obtained which is compatible with measurements of this quantity in lattice Yang-Mills theory. (C) 2000 Elsevier Science B.V. All rights reserved.