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arXiv · hep-lat/0402002

Low-energy couplings of QCD from current correlators near the chiral limit

L. Giusti·P. Hernandez·M. Laine·P. Weisz·H. Wittig
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Abstract

We investigate a new numerical procedure to compute fermionic correlation functions at very small quark masses. Large statistical fluctuations, due to the presence of local ``bumps'' in the wave functions associated with the low-lying eigenmodes of the Dirac operator, are reduced by an exact low-mode averaging. To demonstrate the feasibility of the technique, we compute the two-point correlator of the left-handed vector current with Neuberger fermions in the quenched approximation, for lattices with a linear extent of L~1.5 fm, a lattice spacing a~0.09 fm, and quark masses down to the epsilon-regime. By matching the results with the corresponding (quenched) chiral perturbation theory expressions, an estimate of (quenched) low-energy constants can be obtained. We find agreement between the quenched values of F extrapolated from the p-regime and extracted in the epsilon-regime.

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L. Giusti, P. Hernandez, M. Laine, P. Weisz, H. Wittig. 2004-04-22. Low-energy couplings of QCD from current correlators near the chiral limit. https://doi.org/10.1088/1126-6708%2F2004%2F04%2F013

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