Unquenched QCD simulation results

TL;DR

This paper reviews recent progress in unquenched QCD simulations, comparing hadron spectra from quenched and unquenched approaches, and discusses dynamical quark effects on various physical quantities.

Contribution

It provides a critical review of unquenched QCD simulation results, highlighting discrepancies between different quark actions and analyzing dynamical quark effects on hadron spectra and other observables.

Findings

Discrepancies in the Edinburgh plot between Wilson and KS quark actions.

Dynamical quark effects significantly influence meson masses.

Effects on topological susceptibility and flavor-singlet meson mass are discussed.

Abstract

The recent progress on unquenched QCD simulations is critically reviewed. After some discussions on problems and subtleties in unquenched simulations, hadron spectra obtained from both quenched and unquenched simulations are compared among various gauge and quark actions. It is found that the Edinburgh plot does not agree in the continuum limit between Wilson and KS quark actions even in quenched QCD. Dynamical quark effects on hadron spectra, in particular, on meson masses are then presented for Wilson-type quark actions. Finally dynamical quark effects on other quantities such as the topological susceptibility and the flavor-singlet meson mass are discussed.