7,150 research outputs found
Two flavors of dynamical quarks on anisotropic lattices
We report on our study of two-flavor full QCD on anisotropic lattices using
-improved Wilson quarks coupled with an RG-improved glue. The bare gauge
and quark anisotropies corresponding to the renormalized anisotropy
are determined as functions of and , which
covers the region of spatial lattice spacings --0.16 fm and
--0.9. The calibrations of the bare anisotropies are
performed with the Wilson loop and the meson dispersion relation at 4 lattice
cutoffs and 5--6 quark masses. Using the calibration results we calculate the
meson mass spectrum and the Sommer scale . We confirm that the values of
calculated for the calibration using pseudo scalar and vector meson
energy momentum dispersion relation coincide in the continuum limit within
errors. This work serves to lay ground toward studies of heavy quark systems
and thermodynamics of QCD including the extraction of the equation of state in
the continuum limit using Wilson-type quark actions.Comment: 16 pages, 23 figures, Version accepted for publication in Physical
Review
Renormalization group improved action on anisotropic lattices
We study a block spin transformation in the SU(3) lattice gauge theory on
anisotropic lattices to obtain Iwasaki's renormalization group improved action
for anisotropic cases. For the class of actions with plaquette and
rectangular terms, we determine the improvement parameters as functions of the
anisotropy . We find that the program of improvement works well
also on anisotropic lattices. From a study of an indicator which estimates the
distance to the renormalized trajectory, we show that, for the range of the
anisotropy --4, the coupling parameters previously determined
for isotropic lattices improve the theory considerably.Comment: 15 pages, 10 figure
Finite-size-scaling functions for 3d O(4) and O(2) spin models and QCD
We calculate numerically universal finite-size-scaling functions for the
three-dimensional O(4) and O(2) models. The approach of these functions to the
infinite-volume scaling functions is studied in detail on the critical and
pseudocritical lines. For this purpose we determine the pseudocritical line in
two different ways. We find that the asymptotic form of the finite-size-scaling
functions is already reached at small values of the scaling variable. A
comparison with QCD lattice data for two flavours of staggered fermions shows a
similar finite-size behaviour which is compatible with that of the spin models.Comment: 14 pages, 14 Ps-figures, Latex2
Perturbative renormalization factors in domain-wall QCD with improved gauge actions
We evaluate renormalization factors of the domain-wall fermion system with
various improved gauge actions at one loop level. The renormalization factors
are calculated for quark wave function, quark mass, bilinear quark operators,
three- and four-quark operators in modified minimal subtraction (MS-bar) scheme
with the dimensional reduction(DRED) as well as the naive dimensional
regularization(NDR). We also present detailed results in the mean field
improved perturbation theory.Comment: 44 page
Scaling behavior of with NRQCD
We investigate the scaling behavior of the meson decay constant and
at , employing the NRQCD heavy quark
action and the clover light quark action. Mixing effect from dimension-4
operator in the heavy-light axial-vector current is studied, and we find that
the dependence of is significantly reduced. Our preliminary result
for the decay constants in the quenched approximation is
MeV, MeV, and
.Comment: LATTICE98(matrixelement), 3 pages, 3 eps figure
NRQCD Results on Form Factors
We report results on and semi-leptonic decay form factors using
NRQCD. We investigate scaling behavior of decay amplitudes. For
Effect of higher order relativistic correction terms are also studied.Comment: 9 pgs. 10 figures. Latex2e. espcrc2.sty included. Talk presented at
the Internatioal Workshop "LATTICE QCD ON PARALLEL COMPUTERS", March 1997,
Tsukub
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