Exploring the epsilon regime with lattice Wilson fermions

Abstract

We study the impact of explicit chiral symmetry breaking of lattice Wilson fermions on mesonic correlators in the epsilon-regime using Wilson chiral perturbation theory. We generalize the epsilon-expansion of continuum chiral perturbation theory to nonzero lattice spacing a and distinguish various regimes. It turnes out that lattice corrections are highly suppressed, as long as quark masses are of the order a\Lambda^2_QCD. The lattice spacing effects become more pronounced for smaller quark masses and may lead to non-trivial corrections of the continuum results at next-to-leading order. We compute these corrections for standard current and density correlation functions. A fit to lattice data shows that these corrections are small, as expected.