UNCERTAINTY BANDS FOR CHIRAL EXTRAPOLATIONS

Lattice QCD results can be extrapolated to physical quark masses using Chiral Perturbation Theory. Here, treatment of statistical and systematic errors is discussed. One way of estimating the theoretical uncertainty is to perform a matching of the theory to a framework with an additional degree of freedom. This is illustrated for the nucleon axial vector coupling constant g_A by effectively integrating out the leading Δ(1232) contribution.