We present a lattice QCD calculation of the low-energy constants of the leading order chiral Lagrangian. In these simulations the epsilon regime is reached by using tree-level improved nHYP Wilson fermions combined with reweighting in the quark mass. We analyze two point functions on two ensembles with lattices of size $(1.85\mathrm{fm}{)}^4$ and $(2.8\mathrm{fm}{)}^4$, and at several quark mass values between 4 and 20 MeV. The data are well fitted with next-to-leading order chiral perturbative formulas and predict $F=90(4)\mathrm{MeV}$ and ${\Sigma }^{1/3}=248(6)\mathrm{MeV}$ in the $\overline{\mathrm{MS}}$ scheme at 2 GeV.

• Received 5 July 2008

DOI:https://doi.org/10.1103/PhysRevD.78.054511