1,176 research outputs found
Matching of the Heavy-Light Currents with NRQCD Heavy and Improved Naive Light Quarks
One-loop matching of heavy-light currents is carried out for a highly
improved lattice action, including the effects of mixings with dimension 4
O(1/M) and O(a) operators. We use the NRQCD action for heavy quarks, the Asqtad
improved naive action for light quarks, and the Symanzik improved glue action.
These results are being used in recent heavy meson decay constant and
semileptonic form factor calculations on the MILC dynamical configurations.Comment: 3 pages, 3 figures. Talk presented at Lattice2004(heavy
B Leptonic Decays and B- bar B Mixing with 2+1 Flavors of Dynamical Quarks
Calculations of B leptonic decays and B- bar B mixing using NRQCD heavy and
Asqtad light valence quarks on the MILC dynamical configurations are described.
Smearing has been implemented to substantially reduce the statistical errors of
the matrix elements needed for the determination of f_B. The four-fermion
matrix elements needed for the determination of f_{B_s}^2B_{B_s} have been
calculated and a preliminary result is given.Comment: 3 pages, 3 figures, talk given at Lattice2004(heavy), Batavia,
Illinois, 21-26 Jun 200
B Decays on the Lattice and Results for Phenomenology
Lattice Monte Carlo simulations now include the effects of 2 light sea quarks
and 1 strange sea quark through the use of an improved staggered fermion
action. Consequently, results important to phenomenology are free of the
approximate 10% errors inherent in the quenched approximation. This talk
reports on calculations of the B and Bs decay constants and B -> pi l nu form
factors. Accurate determinations of these quantities will lead to tighter
constraints on CKM matrix elements.Comment: Contributed to the Proceedings of American Physical Society's 2004
Meeting of the Division of Particles and Fields (DPF2004), Riverside, CA,
26-31 August 2004. 3 page
On the Two-point Correlation of Potential Vorticity in Rotating and Stratified Turbulence
A framework is developed to describe the two-point statistics of potential
vorticity in rotating and stratified turbulence as described by the Boussinesq
equations. The Karman-Howarth equation for the dynamics of the two-point
correlation function of potential vorticity reveals the possibility of
inertial-range dynamics in certain regimes in the Rossby, Froude, Prandtl and
Reynolds number parameters. For the case of large Rossby and Froude numbers,
and for the case of quasi-geostrophic dynamics, a linear scaling law with 2/3
prefactor is derived for the third-order mixed correlation between potential
vorticity and velocity, a result that is analogous to the Kolmogorov 4/5-law
for the third-order velocity structure function in turbulence theory.Comment: 10 pages, to appear in Journal of Fluid Mechanics (2006
Embracing Immigration: Contemporary Japanese College Students Perceptions of Foreign Labor in Japan
Ex Vivo Culture of Chick Cerebellar Slices and Spatially Targeted Electroporation of Granule Cell Precursors
The cerebellar external granule layer (EGL) is the site of the largest transit amplification in the developing brain, and an excellent model for studying neuronal proliferation and differentiation. In addition, evolutionary modifications of its proliferative capability have been responsible for the dramatic expansion of cerebellar size in the amniotes, making the cerebellum an excellent model for evo-devo studies of the vertebrate brain. The constituent cells of the EGL, cerebellar granule progenitors, also represent a significant cell of origin for medulloblastoma, the most prevalent paediatric neuronal tumour. Following transit amplification, granule precursors migrate radially into the internal granular layer of the cerebellum where they represent the largest neuronal population in the mature mammalian brain. In chick, the peak of EGL proliferation occurs towards the end of the second week of gestation. In order to target genetic modification to this layer at the peak of proliferation, we have developed a method for genetic manipulation through ex vivo electroporation of cerebellum slices from embryonic Day 14 chick embryos. This method recapitulates several important aspects of in vivo granule neuron development and will be useful in generating a thorough understanding of cerebellar granule cell proliferation and differentiation, and thus of cerebellum development, evolution and disease
Heavy-Light Meson Semileptonic Decays with Staggered Light Quarks
We report on exploratory studies of heavy-light meson semileptonic decays
using Asqtad light quarks, NRQCD heavy quarks and Symanzik improved glue on
coarse quenched lattices. Oscillatory contributions to three-point correlators
coming from the staggered light quarks are found to be handled well by Bayesian
fitting methods. B meson decays to both the Goldstone pion and to one of the
point-split non-Goldstone pions are investigated. One-loop perturbative
matching of NRQCD/Asqtad heavy-light currents is incorporated.Comment: 3 pages, 3 postscript figures, Lattice2003(heavy
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