Evidence for instanton induced dynamics, from lattice QCD
Apr, 2003
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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.- fermion: lattice field theory
- quantum chromodynamics
- symmetry: chiral
- correlation function
- quark quark: interaction
- nonperturbative
- instanton: liquid
- unitarity
- Dyson-Schwinger equation
- numerical calculations: Monte Carlo
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