Exploration of sea quark effects in two-flavor QCD with the O(a)-improved Wilson quark action

TL;DR

This study investigates how sea quark effects influence the light hadron mass spectrum in two-flavor QCD using an improved Wilson quark action, highlighting finite-size effects and deviations from quenched approximations.

Contribution

It provides the first detailed analysis of sea quark effects on meson masses using nonperturbatively improved Wilson fermions across multiple lattice sizes.

Findings

Strange vector meson mass increases significantly compared to quenched approximation.

Finite-size effects are negligible on the largest lattice.

Results are consistent with (partially quenched) chiral perturbation theory.

Abstract

We explore sea quark effects in the light hadron mass spectrum in a simulation of two-flavor QCD using the nonperturbatively O(a)-improved Wilson fermion action. In order to identify finite-size effects, light meson masses are measured on 12^3x48, 16^3x48 and 20^3x48 lattices with a~0.1 fm. On the largest lattice, where the finite-size effect is negligible, we find a significant increase of the strange vector meson mass compared to the quenched approximation. We also investigate the quark mass dependence of pseudoscalar meson masses and decay constants and test the consistency with (partially quenched) chiral perturbation theory.