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arXiv · hep-ph/0304219

Evidence for Instanton-Induced Dynamics, from Lattice QCD

Pietro Faccioli·Thomas A. DeGrand
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Abstract

We perform a study of the non-perturbative dynamics of the light-quark sector of QCD, based on some recent results of lattice simulations with chiral fermions. We analyze some correlators that are designed to probe the Dirac structure of the quark-quark interaction at different scales. We show that, in the non-perturbative regime, such an interaction contains very large scalar and pseudo-scalar components. We observe quantitative agreement between lattice QCD results and the predictions of the Instanton Liquid Model (ILM). Moreover, we study how the the quark-quark interaction is modified, when quark loops are suppressed. We observe a dramatic effect related to the loss of unitarity, which is naturally explained in the instanton picture. Such an effect cannot be explained in a Dyson-Schwinger Equations (DSE) approach, if one assumes a simple vector quark-gluon coupling. Therefore, from the present study it emerges that DSE models with such an ansatz for the vertex function are not consistent with QCD.

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Pietro Faccioli, Thomas A. DeGrand. 2003-09-10. Evidence for Instanton-Induced Dynamics, from Lattice QCD. https://doi.org/10.1103/physrevlett.91.182001

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