Instanton contributions to the low-lying hadron mass spectrum

Abstract

The role of instanton-like objects in the QCD vacuum on the mass spectrum of low-lying light hadrons is explored in lattice QCD. Using over-improved stout-link smearing, tuned to preserve instanton-like objects in the QCD vacuum, the evolution of the mass spectrum under smearing is examined. The calculation is performed using a $20^3\times 40$ dynamical fat-link-irrelevant-clover (FLIC) fermion action ensemble with lattice spacing 0.126 fm. Through the consideration of a range of pion masses, the effect of the vacuum instanton content is compared at a common pion mass. While the qualitative features of ground-state hadrons are preserved on instanton-dominated configurations, the excitation spectrum experiences significant changes. The underlying physics revealed shows little similarity to the direct-instanton interaction predictions of the instanton liquid model.

11 pages, 17 figures

References in corpus (6)

• Comparison of the gradient flow with cooling in $SU(3)$ pure gauge theory
• Over-Improved Stout-Link Smearing
• Nucleon Excited State Wave Functions from Lattice QCD
• Impact of Dynamical Fermions on QCD Vacuum Structure
• Quark Propagation in the Instantons of Lattice QCD
• On Chiral Symmetry Breaking, Topology and Confinement

Cited by in corpus (4)

• Gluon propagator on a centre-vortex background
• Centre vortex removal restores chiral symmetry
• On the equivalence between the Wilson flow and stout-link smearing
• Numerical evidence for fractional topological objects in SU(3) gauge theory