Exploring the chiral regime of $N_f=2$ QCD with mixed actions

TL;DR

This paper investigates the chiral properties of two-flavor QCD using mixed-action lattice simulations, matching lattice results to chiral perturbation theory to extract low-energy constants.

Contribution

It introduces a novel approach combining Neuberger valence fermions with Wilson sea quarks in the mixed-regime to study chiral symmetry breaking.

Findings

Determined low-energy constants $\Sigma$, $L_6$, and $L_8+2L_6+2L_7$ from lattice data.

Validated the mixed-regime matching between lattice QCD and chiral perturbation theory.

Abstract

We report on our simulations with Neuberger valence fermions on CLS $N_f=2$ configurations with non-perturbatively $O(a)$-improved Wilson sea quarks. We consider the matching of QCD to ChPT in the so called mixed-regime in which the sea quarks are in the $p$-regime while the valence quarks are in the $\epsilon$-regime. From this matching, we can get information on $\Sigma$, $L_6$ and the combination $L_8+2L_6+2L_7$.