Low energy chiral constants from epsilon-regime simulations with improved Wilson fermions

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 fm)⁴ and (2.8 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) MeV and Σ1/3=248(6) MeV in the MS̄ scheme at 2 GeV.