Meson correlators in the epsilon-regime of two-flavor lattice QCD

TL;DR

This study computes meson correlators in the epsilon-regime of two-flavor lattice QCD using dynamical overlap fermions, extracting key low-energy constants by comparing with chiral perturbation theory predictions.

Contribution

It provides a precise lattice calculation of meson correlators in the epsilon-regime and determines the pion decay constant and chiral condensate with high accuracy.

Findings

Extracted pion decay constant F = 87.3(5.5) MeV.

Determined chiral condensate Σ^{MS} = [237.8(4.0) MeV]^3.

Validated chiral perturbation theory predictions in the epsilon-regime.

Abstract

We calculate the meson correlators in the $\epsilon$-regime of two-flavor QCD. On a $16^3\times 32$ lattice with $a\sim 0.11$ fm, the lattice simulations are performed with the dynamical overlap fermions. We reduce the sea quark mass down to $\sim$ 3 MeV and the valence quark masses are taken in the range 1-4 MeV. The meson correlators in various channels are compared with the predictions of (partially quenched) chiral perturbation theory (ChPT). Including the NLO order of the $\epsilon$-expansion, we extract the leading-order low energy constants of ChPT, the pion decay constant $F$ and the chiral condensate $\Sigma$, as $F=87.3(5.5)$ MeV and $\Sigma^{\bar{\mathrm{MS}}}=[237.8(4.0){MeV}]^3$.