209 research outputs found
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
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
Multidimensional analysis of human intestinal fluid composition
The oral administration of solid dosage forms is the commonest method to achieve systemic therapy and relies on the drug’s solubility in human intestinal fluid (HIF), a key factor that influences bioavailability and biopharmaceutical classification. However, HIF is difficult to obtain and is known to be variable, which has led to the development of a range of simulated intestinal fluid (SIF) systems to determine drug solubility in vitro. In this study we have applied a novel multidimensional approach to analyse and characterise HIF composition using a published data set in both fasted and fed states with a view to refining the existing SIF approaches. The data set provided 152 and 172 measurements of five variables (total bile salt, phospholipid, total free fatty acid, cholesterol and pH) in time-dependent HIF samples from 20 volunteers in the fasted and fed state, respectively. The variable data sets for both fasted state and fed state are complex, do not follow normal distributions but the amphiphilic variable concentrations are correlated. When plotted 2-dimensionally a generally ellipsoid shaped data cloud with a positive slope is revealed with boundaries that enclose published fasted or fed HIF compositions. The data cloud also encloses the majority of fasted state and fed state SIF recipes and illustrates that the structured nature of design of experiment (DoE) approaches does not optimally cover the variable space and may examine media compositions that are not biorelevant. A principal component analysis in either fasted or fed state in combination with fitting an ellipsoid shape to enclose the data results in 8 points that capture over 95% of the compositional variability of HIF. The variable’s average rate of concentration change in both fasted state and fed state over a short time scale (10 min) is zero and a Euclidean analysis highlights differences between the fasted and fed states and among individual volunteers. The results indicate that a 9-point DoE (8 + 1 central point) could be applied to investigate drug solubility in vitro and provide statistical solubility limits. In addition, a single point could provide a worst-case solubility measurement to define the lowest biopharmaceutical classification boundary or for use during drug development. This study has provided a novel description of HIF composition. The approach could be expanded in multiple ways by incorporation of further data sets to improve the statistical coverage or to cover specific patient groups (e.g., paediatric). Further development might also be possible to analyse information on the time dependent behaviour of HIF and to guide HIF sampling and analysis protocols
One-loop renormalization of heavy-light currents
We calculate the mass dependent renormalization factors of heavy-light
bilinears at one-loop order of perturbation theory, when the heavy quark is
treated with the Fermilab formalism.
We present numerical results for the Wilson and Sheikholeslami-Wohlert
actions, with and without tree-level rotation.
We find that in both cases our results smoothly interpolate from the static
limit to the massless limit.
We also calculate the mass dependent Brodsky-Lepage-Mackenzie scale ,
with and without tadpole-improvement.Comment: Lattice2001(improvement), 3 pages, 4 figure
A lattice NRQCD calculation of the mixing parameter B_B
We present a lattice calculation of the B meson B-parameter B_B using the
NRQCD action. The heavy quark mass dependence is explicitly studied over a mass
range between m_b and 4m_b with the and actions. We
find that the ratios of lattice matrix elements and
, which contribute to B_B through mixing, have
significant dependence while that of the leading operator
has little effect. The combined result for
B_B(m_b) has small but non-zero mass dependence, and the B_B(m_b) becomes
smaller by 10% with the 1/m_Q correction compared to the static result. Our
result in the quenched approximation at \beta=5.9 is B_{B_d}(5 GeV) =
0.75(3)(12), where the first error is statistical and the second is a
systematic uncertainty.Comment: 20 pages, 11 figures, uses REVTeX, typos correcte
A Study of Meson Correlators at Finite Temperature
We present results for mesonic propagators in temporal and spatial directions
at T below and above the deconfining transition in quenched QCD. Anisotropic
lattices are used to get enough information in the temporal direction. We use
the Wilson fermion action for light quarks and Fermilab action for heavy
quarks.Comment: LATTICE 99 (finite temperature and density), 3 pages, LaTeX with 3
eps figures, espcrc2.sty, psfig.st
Multi-modal dissolution testing system for pharmaceutical tablets
This project aims to develop a novel multimodal sensor system that is capable of resolving the key processes, as well as how these processes are linked to microstructure, formulation and raw material attributes
Lattice QCD calculation of decay form factors at zero recoil
A lattice QCD calculation of the decay form factors
is presented. We obtain the value of the form factor at the
zero-recoil limit with high precision by considering a ratio of
correlation functions in which the bulk of the uncertainties cancels. The other
form factor is calculated, for small recoil momenta, from a similar
ratio. In both cases, the heavy quark mass dependence is observed through
direct calculations with several combinations of initial and final heavy quark
masses. Our results are and
. For both the first error is statistical,
the second stems from the uncertainty in adjusting the heavy quark masses, and
the last from omitted radiative corrections. Combining these results, we obtain
a precise determination of the physical combination , where the mentioned systematic errors are added in
quadrature. The dependence on lattice spacing and the effect of quenching are
not yet included, but with our method they should be a fraction of .Comment: 32 pp, 10 figs; final, published versio
Heavy quark mass dependence of semileptonic form factors for B decays
We present our study of the dependence of the heavy-to-light semileptonic B
decay form factors on the heavy-light meson mass . Simulations are made
over a range of the heavy quark mass covering both the charm and bottom quarks
using the -improved clover action at on a and
lattice. We find that a weak dependence of form factors on
observed in previous studies in the region of charm quark persists up
to the region of quark. The soft pion relation is
examined and found to be largely violated.Comment: 3 pages, latex source-file, 4 figures as epsf-file, uses espcrc2.sty.
Talk presented by S. Tominaga at Lattice 97, Edinburgh, Scotland, 22-26 Jul
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