Non-perturbative chiral corrections for lattice QCD

Abstract

We explore the chiral aspects of extrapolation of observables calculated within lattice QCD, using the nucleon magnetic moments as an example. Our analysis shows that the biggest effects of chiral dynamics occur for quark masses corresponding to a pion mass below 600 MeV. In this limited range chiral perturbation theory is not rapidly convergent, but we can develop some understanding of the behaviour through chiral quark models. This model dependent analysis leads us to a simple Pad\'e approximant which builds in both the limits $m_\pi \to 0$ and $m_\pi \to \infty$ correctly and permits a consistent, model independent extrapolation to the physical pion mass which should be extremely reliable.