661 research outputs found
Leptonic decay constants f_Ds and f_D in three flavor lattice QCD
We determine the leptonic decay constants in three flavor unquenched lattice
QCD. We use O(a^2)-improved staggered light quarks and O(a)-improved charm
quarks in the Fermilab heavy quark formalism. Our preliminary results, based
upon an analysis at a single lattice spacing, are f_Ds = 263(+5-9)(+/-24) MeV
and f_D = 225(+11-13)(+/-21) MeV. In each case, the first reported error is
statistical while the is the combined systematic uncertainty.Comment: Talk presented at Lattice2004(heavy), Fermilab, June 21-26, 2004. 3
pages, 2 figure
Bc Meson Formfactors and Bc-->PV Decays Involving Flavor Dependence of Transverse Quark Momentum
We present a detailed analysis of the Bc form factors in the BSW framework,
by investigating the effects of the flavor dependence on the average transverse
quark momentum inside a meson. Branching ratios of two body decays of Bc meson
to pseudoscalar and vector mesons are predicted.Comment: 18 pages, 5 figure
Recent results from lattice calculations
Recent results from lattice QCD calculations relevant to particle physics
phenomenology are reviewed. They include the calculations of strong coupling
constant, quark masses, kaon matrix elements, and D and B meson matrix
elements. Special emphasis is on the recent progress in the simulations
including dynamical quarks.Comment: 13 pages, 8 figures, plenary talk at the 32nd International
Conference on High-Energy Physics (ICHEP 2004), August 16-22, 2004, Beijing,
Chin
High-Precision Lattice QCD Confronts Experiment
We argue that high-precision lattice QCD is now possible, for the first time,
because of a new improved staggered quark discretization. We compare a wide
variety of nonperturbative calculations in QCD with experiment, and find
agreement to within statistical and systematic errors of 3% or less. We also
present a new determination of alpha_msbar(Mz); we obtain 0.121(3). We discuss
the implications of this breakthrough for phenomenology and, in particular, for
heavy-quark physics.Comment: 2 figures, revte
Prospects for the Bc Studies at LHCb
We discuss the motivations and perspectives for the studies of the mesons of
the (bc) family at LHCb. The description of production and decays at LHC
energies is given in details. The event yields, detection efficiencies, and
background conditions for several Bc decay modes at LHCb are estimated.Comment: 20 pages, 5 eps-figure
Predictions from Lattice QCD
In the past year, we calculated with lattice QCD three quantities that were
unknown or poorly known. They are the dependence of the form factor in
semileptonic decay, the decay constant of the meson, and the
mass of the meson. In this talk, we summarize these calculations, with
emphasis on their (subsequent) confirmation by experiments.Comment: v1: talk given at the International Conference on QCD and Hadronic
Physics, Beijing, June 16-20, 2005; v2: poster presented at the XXIIIrd
International Symposium on Lattice Field Theory, Dublin, July 25-3
Tuning Fermilab Heavy Quarks in 2+1 Flavor Lattice QCD with Application to Hyperfine Splittings
We report the non-perturbative tuning of parameters--- kappa_c, kappa_b, and
kappa_crit ---that determine the heavy-quark mass in the Fermilab action. This
requires the computation of the masses of Ds^(*) and Bs^(*) mesons comprised of
a Fermilab heavy quark and a staggered light quark. Additionally, we report the
hyperfine splittings for Ds and Bs mesons as a cross-check of our simulation
and analysis methods. We find a splitting of 145 +/- 15 MeV for the Ds system
and 40 +/- 9 MeV for the Bs system. These are in good agreement with the
Particle Data Group average values of 143.9 +/- 0.4 MeV and 46.1 +/- 1.5 MeV,
respectively. The calculations are carried out with the MILC 2+1 flavor gauge
configurations at three lattice spacings approximately 0.15, 0.12, and 0.09
fm.Comment: 34 pages, 8 figures, 26 tables; some sections rearranged for clarity;
conclusions unchanged; version accepted by Phys. Rev.
Branching ratios of Bc Meson Decaying to Pseudoscalar and Axial-Vector Mesons
We study Cabibbo-Kobayashi-Maskawa (CKM) favored weak decays of Bc mesons in
the Isgur-Scora-Grinstein-Wise (ISGW) quark model. We present a detailed
analysis of the Bc meson decaying to a pseudoscalar meson (P) and an
axial-vector meson (A). We also give the form factors involving transition in
the ISGW II framework and consequently, predict the branching ratios of decays.Comment: 19 pages,7 table
Semileptonic D->pi/K and B->pi/D decays in 2+1 flavor lattice QCD
We present results for form factors of semileptonic decays of and
mesons in 2+1 flavor lattice QCD using the MILC gauge configurations. With an
improved staggered action for light quarks, we successfully reduce the
systematic error from the chiral extrapolation. The results for decays are
in agreement with experimental ones. The results for B decays are preliminary.
Combining our results with experimental branching ratios, we then obtain the
CKM matrix elements , , and . We also
check CKM unitarity, for the first time, using only lattice QCD as the
theoretical input.Comment: Talk presented at Lattice2004(heavy); 3 pages, 3 figure
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