Low-energy couplings of QCD from current correlators near the chiral limit
Feb, 2004
19 pages
Published in:
- JHEP 04 (2004) 013
e-Print:
- hep-lat/0402002 [hep-lat]
Report number:
- BI-TP-2004-03,
- CPT-2003-P-4622,
- DESY-04-009,
- FTUV-04-0203,
- IFIC-04-04,
- MPP-2004-6
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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.- quantum chromodynamics
- fermion: correlation function
- current: vector
- current: left-handed
- fermion: lattice field theory
- approximation: quenching
- coupling constant
- perturbation theory: chiral
- numerical calculations: Monte Carlo
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