569 research outputs found
The double charm decays of Meson in the Perturbative QCD Approach
We make a systematic investigation on the double charm decays of meson,
by employing the perturbative QCD approach based on factorization. It is
found that the non-factorizable emission diagrams are not negligible in these
channels. We predict the branching ratios of these decays and also the
transverse polarization fractions of decays, % where V denote the vector meson.
We find that the magnitudes of the branching ratios of the decays
and are very close to
each other, which are well suited to extract the Cabibbo-Kobayashi-Maskawa
angle through the amplitude relations. In addition, a large transverse
polarization contribution that can reach is predicted in some of
the meson decay to two vector charmed mesons.Comment: 22 pages, 5 tables, to appear at PRD. arXiv admin note: text overlap
with arXiv:1112.125
Non-leptonic two-body decays of the Bc meson in light-front quark model and QCD factorization approach
We study exclusive non-leptonic two-body
decays with (pseudoscalar or vector meson) being factored out in QCD
factorization approach. The non-leptonic decay amplitudes are related to the
product of meson decay constants and the form factors for semileptonic
decays. As inputs in obtaining the branching ratios for a large set of
non-leptonic decays, we use the weak form factors for the semileptonic
decays in the whole kinematical region and the
unmeasured meson decay constants obtained from our previous light-front quark
model. We compare our results of the branching ratios with those of other
theoretical studies.Comment: 11 pages, 3 figures, minor corrections, version to appear in PR
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
Calculation of the B_{c}leptonic decay constant using the shifted N-expansion method
We give a review and present a comprehensive calculation for the leptonic
constant B_{c} of the low-lying pseudoscalar and vector states of B_{c}-meson
in the framework of static and QCD-motivated nonrelativistic potential models
taking into account the one-loop and two-loop QCD corrections in the short
distance coefficient that governs the leptonic constant of quarkonium
system. Further, we use the scaling relation to predict the leptonic constant
of the nS-states of the (b_bar)c system. Our results are compared with other
models to gauge the reliability of the predictions and point out differences.Comment: 26 page
The Decays to -wave Charmonium by Improved Bethe-Salpeter Approach
We re-calculate the exclusive semileptonic and nonleptonic decays of
meson to a -wave charmonium in terms of the improved Bethe-Salpeter (B-S)
approach, which is developed recently. Here the widths for the exclusive
semileptonic and nonleptonic decays, the form factors, and the charged lepton
spectrums for the semileptonic decays are precisely calculated. To test the
concerned approach by comparing with experimental measurements when the
experimental data are available, and to have comparisons with the other
approaches the results obtained by the approach and those by some approaches
else as well as the original B-S approach, which appeared in literature, are
comparatively presented and discussed.Comment: 33 pages, 5 figures, 3 table
Gold-plated Mode of CP-Violation in Decays of B_c Meson from QCD Sum Rules
The model-independent method based on the triangle ideology is implemented to
extract the CKM-matrix angle gamma in the decays of doubly heavy long-lived
meson B_c. We analyze a color structure of diagrams and conditions to
reconstruct two reference-triangles by tagging the flavor and CP eigenstates of
D^0 meson in the fixed exclusive channels. The characteristic branching ratios
are evaluated in the framework of QCD sum rules.Comment: 11 pages, RevTeX4 file, 4 eps-figure
Search for charginos in e+e- interactions at sqrt(s) = 189 GeV
An update of the searches for charginos and gravitinos is presented, based on
a data sample corresponding to the 158 pb^{-1} recorded by the DELPHI detector
in 1998, at a centre-of-mass energy of 189 GeV. No evidence for a signal was
found. The lower mass limits are 4-5 GeV/c^2 higher than those obtained at a
centre-of-mass energy of 183 GeV. The (\mu,M_2) MSSM domain excluded by
combining the chargino searches with neutralino searches at the Z resonance
implies a limit on the mass of the lightest neutralino which, for a heavy
sneutrino, is constrained to be above 31.0 GeV/c^2 for tan(beta) \geq 1.Comment: 22 pages, 8 figure
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