1,218 research outputs found
Nucleon strange quark content from two-flavor lattice QCD with exact chiral symmetry
Strange quark content of the nucleon is calculated in dynamical lattice QCD
employing the overlap fermion formulation. For this quantity, exact chiral
symmetry guaranteed by the Ginsparg-Wilson relation is crucial to avoid large
contamination due to a possible operator mixing with . Gauge
configurations are generated with two dynamical flavors on a 16^3 x 32 lattice
at a lattice spacing a \simeq 0.12fm. We directly calculate the relevant
three-point function on the lattice including a disconnected strange quark loop
utilizing the techniques of all-to-all quark propagator and low-mode averaging.
Our result f_{T_s} = 0.032(8)(22), is in good agreement with our previous
indirect estimate using the Feynman-Hellmann theorem.Comment: 31 pages, 22 figures; version published in PR
Dual-camera system for high-speed imaging in particle image velocimetry
Particle image velocimetry is an important technique in experimental fluid
mechanics, for which it has been essential to use a specialized high-speed
camera. However, the high speed is at the expense of other performances of the
camera, i.e., sensitivity and image resolution. Here, we demonstrate that the
high-speed imaging is also possible with a pair of still cameras.Comment: 4 pages, accepted by Journal of Visualization (see
http://www.springerlink.com
Topology conserving gauge action and the overlap-Dirac operator
We apply the topology conserving gauge action proposed by Luescher to the
four-dimensional lattice QCD simulation in the quenched approximation. With
this gauge action the topological charge is stabilized along the hybrid Monte
Carlo updates compared to the standard Wilson gauge action. The quark potential
and renormalized coupling constant are in good agreement with the results
obtained with the Wilson gauge action. We also investigate the low-lying
eigenvalue distribution of the hermitian Wilson-Dirac operator, which is
relevant for the construction of the overlap-Dirac operator.Comment: 27pages, 11figures, accepted versio
matching coefficients for axial vector current and 2 operator
We present a calculation of the perturbative matching coefficients including
mixing with higher dimensional operators for the temporal component of the
heavy-light axial current, , and the operator, . For
, calculations with various RG-improved
gauge actions are peformed. Matching coefficients with NRQCD and heavy-clover
actions are also compared.Comment: LATTICE99 (Heavy Quarks), 3 pages, 2 figures, espcrc2.st
First study of semileptonic decay form factors using NRQCD
We present a quenched calculation of the form factors of the semileptonic
weak decay with NRQCD heavy quark and Wilson
light quark on a lattice at . The form factors are
evaluated at six heavy quark masses, in the range of GeV.
dependence of matrix elements are investigated and compared with HQET
predictions. We observe clear signal for the form factors near ,
even at the -quark mass range. is compared with
based on the soft pion theorem and significant difference is
observed.Comment: 3 pages, 5 ps figures, uses espcrc2.sty and epsf.sty, Talk presented
at Lattice'9
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