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arXiv · 1410.7105

Instanton contributions to the low-lying hadron mass spectrum

Samuel D. Thomas·Waseem Kamleh·Derek B. Leinweber
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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 $20^3\times40$ 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.

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Samuel D. Thomas, Waseem Kamleh, Derek B. Leinweber. 2015-09-23. Instanton contributions to the low-lying hadron mass spectrum. https://doi.org/10.1103/physrevd.92.094515

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