Low-Lying Mode Contribution to the Quenched Meson Correlators in the ε-Regime(Particles and Fields)

概要

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We present a quenched calculation of meson correlators using the overlap fermion with very small masses, 2.6-13MeV. In this region, the pion Compton wavelength is larger than our lattice size (L≃1.23fm), and the system is in the so-called ε-regime of chiral perturbation theory. We find that the scalar and pseudo-scalar correlators are accurately approximated by a few hundred low-lying fermion eigenmodes in this regime, whereas the axial-vector correlator contains significant contributions from higher eigenmodes. We also compute the disconnected pseudo-scalar correlator, which is well saturated with low-lying modes. Matching these lattice data with the one-loop expressions for the correlators in quenched chiral perturbation theory, we evaluate the decay constant F_π and the chiral condensate Σ, as well as the parameters m^2_0 and α, which describe the artifacts of the quenched approximation.
理論物理学刊行会の論文
2005-08-25