Exploring the epsilon regime with lattice Wilson fermions

TL;DR

This paper investigates how lattice Wilson fermions affect mesonic correlators in the epsilon-regime, extending chiral perturbation theory to include lattice spacing effects and finding that corrections are generally small.

Contribution

It generalizes the epsilon-expansion of chiral perturbation theory to nonzero lattice spacing and quantifies the impact of lattice corrections on mesonic correlators.

Findings

Lattice corrections are highly suppressed when quark masses are of order aΛ_QCD^2.

Corrections become more significant at smaller quark masses, potentially affecting continuum results.

Fitted lattice data indicates these corrections are small, validating the theoretical approach.

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.