134 research outputs found
Weak Decays of Heavy-Light Mesons on the Lattice: Semi-Leptonic Formfactors
We report results (on an intermediate statistics sample) of a study of weak
semi-leptonic formfactors of and decays, addressing the uncertainties
from mass extrapolations to chiral and to heavy quarks. Moreover, we present a
nonperturbative test to the LMK current renormalization scheme for vector
current {\it transition} matrix elements and find remarkable agreement.Comment: 13 pages, uuencoded, updated table
Heavy-light baryonic mass splittings from the lattice
We present lattice estimates of the mass of the heavy-light baryons
and obtained using propagating heavy quarks. For
our result is GeV, after
extrapolation to the continuum limit and in the quenched approximation.Comment: 3 pages postscript, Contribution to Lattice'9
Semileptonic Decays of D and B Mesons
We report results of our ongoing investigation concerning semileptonic decays
of heavy pseudoscalar mesons into pseudoscalar and vector mesons. Particular
attention is paid to uncertainties in the and the heavy quark mass
dependence of formfactors. Moreover we present a non-perturbative test to the
LMK current renormalization scheme for vector current transition matrix
elements and find remarkable agreement.Comment: 3 pages, uuencoded, contribution to Lat 9
Semileptonic Decays of Heavy Mesons: A Status Report
We present intermediate results on our ongoing investigation concerning
semileptonic decays of heavy pseudoscalar mesons into pseudoscalar and vector
mesons. The corresponding formfactors are evaluated at several momenta and
appropriate combinations of four light and four heavy quarks, which are chosen
to allow for an extrapolation into the B Meson region. In order to obtain clear
groundstate signals we apply gauge invariant ``Wuppertal'' smearing to the
quarks. The analysis is based on 32 quenched gauge configurations of size at , with Wilson fermions.Comment: 3 pages, uuencoded, contribution to Lat 9
Beautiful Baryons from Lattice QCD
We perform a lattice study of heavy baryons, containing one () or
two -quarks (). Using the quenched approximation we obtain for the
mass of
The mass splitting between the and the B-meson is found to increase
by about 20\% if the light quark mass is varied from the chiral limit to the
strange quark mass.Comment: 11 pages, Figures obtained upon request from [email protected]
Improved Upsilon Spectrum with Dynamical Wilson Fermions
We present results for the b \bar b spectrum obtained using an
O(M_bv^6)-correct non-relativistic lattice QCD action, where M_b denotes the
bare b-quark mass and v^2 is the mean squared quark velocity. Propagators are
evaluated on SESAM's three sets of dynamical gauge configurations generated
with two flavours of Wilson fermions at beta = 5.6. These results, the first of
their kind obtained with dynamical Wilson fermions, are compared to a quenched
analysis at equivalent lattice spacing, beta = 6.0. Using our three sea-quark
values we perform the ``chiral'' extrapolation to m_eff = m_s/3, where m_s
denotes the strange quark mass. The light quark mass dependence is found to be
small in relation to the statistical errors. Comparing the full QCD result to
our quenched simulation we find better agreement of our dynamical data with
experimental results in the spin-independent sector but observe no unquenching
effects in hyperfine-splittings. To pin down the systematic errors we have also
compared quenched results in different ``tadpole'' schemes as well as using a
lower order action. We find that spin-splittings with an O(M_bv^4) action are
O(10%) higher compared to O(M_bv^6) results. Relative to the results obtained
with the plaquette method the Landau gauge mean link tadpole scheme raises the
spin splittings by about the same margin so that our two improvements are
opposite in effect.Comment: 24 pages (latex file, Phys Rev D style file, uses epsf-style
Phenomenology with Wilson fermions using smeared sources
We investigate the use of two types of non-local (``smeared'') sources for
quark propagators in quenched lattice QCD at using Wilson fermions
at and . We present results for the hadron mass spectrum,
meson decay constants, quark masses, the chiral condensate and the quark
distribution amplitude of the pion. The use of smeared sources leads to a
considerable improvement over previous results. We find a disturbing
discrepancy between the baryon spectra obtained using Wuppertal and wall
sources. We find good signals in the ratio of correlators used to calculate the
quark mass and the chiral condensate and show that the extrapolation to the
chiral limit is smooth.Comment: (revised), 57 pages (29 pages of PostScript in landscape mode, 765924
bytes
- …