Topological susceptibility in full QCD with Ginsparg-Wilson fermions

We show that, if the formula for the topological charge density operator suggested by the use of fermions obeying the Ginsparg-Wilson relation is employed, it is possible to give a precise and unambiguous definition of the topological susceptibility in full QCD, X-tL(full), for finite quark masses on the lattice. The lattice expression of X-tL(full) looks like the formal continuum one, in the sense that no power divergent subtractions are needed for its proper definition. As a consequence, the small mass X-tL(full) leads directly to a multiplicative renormalizable definition of the chiral condensate that does not require any behaviour of X-tL(full) power divergent subtraction. (C) 2004 Published by Elsevier B.V.