Particle theory

Abstract:

We investigate how topological zero-modes affect hadron physics in the quenched approximation. We remark that in a finite volume the exact zero-modes render the chiral condensate pathological and explain why this is not observed in lattice calculations. We then provide an argument, supported by a model calculation, to show how the mixed 'zero-modes' produce a density of modes, λ, in the large volume limit that diverges as 1/√λ. This implies that the quark physics of quenched QCD becomes pathological in the continuum limit. We also show how similar arguments lead to a non-standard but regular spectrum in full QCD. © 1995 Elsevier Science B.V. All rights reserved.