Light meson spectrum with $N_f=2+1$ dynamical overlap fermions

TL;DR

This paper presents a numerical study of the light meson spectrum using 2+1 dynamical overlap fermions, analyzing pseudoscalar masses and decay constants across various quark masses, and examining the applicability of chiral perturbation theory.

Contribution

It provides new lattice QCD results with overlap fermions for 2+1 flavors and assesses chiral perturbation theory's validity in this context.

Findings

Pseudoscalar masses and decay constants computed at five quark masses.

Chiral perturbation theory one-loop formulae are not directly applicable in the strange quark mass region.

Extrapolation to the chiral limit using two-loop chiral perturbation theory.

Abstract

We report on a numerical simulation with 2+1 dynamical flavors of overlap fermions. We calculate pseudo-scalar masses and decay constants on a $16^3\times 48 \times (0.11 {\rm fm})^4$ lattice at five different up and down quark masses and two strange quark masses. The lightest pion mass corresponds to $\approx 310$ MeV. We also study the validity of the chiral perturbation theory using the results of the numerical simulation with two dynamical flavors and conclude that the one-loop formulae cannot be directly applied in the strange quark mass region. We therefore extrapolate our 2+1-flavor results to the chiral limit by fitting the data to the two-loop formulae of the chiral perturbation theory.