4,491 research outputs found
Branching Fractions and CP Asymmetries of the Quasi-Two-Body Decays in within PQCD Approach
Motivated by the first untagged decay-time-integrated amplitude analysis of
decays performed by LHCb collaboration, where the
decay amplitudes are modeled to contain the resonant contributions from
intermediate resonances , and , we
comprehensively investigate the quasi-two-body decays, and calculate the branching fractions and
the time-dependent asymmetries within the perturbative QCD approach based
on the factorization. In the quasi-two-body space region the calculated
branching fractions with the considered intermediate resonances are in good
agreement with the experimental results of LHCb by adopting proper pair
wave function, describing the interaction between the kaon and pion in the
pair. Furthermore,within the obtained branching fractions of the
quasi-two-body decays, we also calculate the branching fractions of
corresponding two-body decays, and the results consist with the LHCb
measurements and the earlier studies with errors. For these considered decays,
since the final states are not flavour-specific, the time-dependent could
be measured. We calculate six -violation observables, which can be tested
in the ongoing LHCb experiment.Comment: 20 page
Cabibbo-Kobayashi-Maskawa-favored decays to a scalar meson and a meson
Within the perturbative QCD approach, we investigated the
Cabibbo-Kobayashi-Maskawa-favored ("" denoting the
scalar meson) decays on the basis of the two-quark picture. Supposing the
scalar mesons are the ground states or the first excited states, we calculated
the the branching ratios of 72 decay modes. Most of the branching ratios are in
the range to , which can be tested in the ongoing LHCb
experiment and the forthcoming Belle-II experiment. Some decays, such as and , could be used to probe the inner structure and the character
of the scalar mesons, if the experiments are available. In addition, the ratios
between the and provide a potential way to determine the mixing
angle between and . Moreover, since in the standard model
these decays occur only through tree operators and have no asymmetries,
any deviation will be signal of the new physics beyond the standard model.Comment: 2 figures, 6 table
The rare semi-leptonic decays involving orbitally excited final mesons
The rare processes , where
stands for the final meson ,
,~, ,
or~, are studied within the Standard Model. The hadronic matrix
elements are evaluated in the Bethe-Salpeter approach and furthermore a
discussion on the gauge-invariant condition of the annihilation hadronic
currents is presented. Considering the penguin, box, annihilation,
color-favored cascade and color-suppressed cascade contributions, the
observables , , and are
calculated
Improved Estimates of The Decays in Perturbative QCD Approach
We reexamine the branching ratios, -asymmetries, and other observables in
a large number of decays in the perturbative QCD (PQCD)
approach, where denotes a light vector meson .
The essential difference between this work and the earlier similar works is of
parametric origin and in the estimates of the power corrections related to the
ratio ( and denote the masses of the
vector and meson, respectively). In particular, we use up-to-date
distribution amplitudes for the final state mesons and keep the terms
proportional to the ratio in our calculations. Our updated calculations
are in agreement with the experimental data, except for a limited number of
decays which we discuss. We emphasize that the penguin annihilation and the
hard-scattering emission contributions are essential to understand the
polarization anomaly, such as in the and
decay modes. We also compare our results with those obtained in the QCD
factorization (QCDF) approach and comment on the similarities and differences,
which can be used to discriminate between these approaches in future
experiments.Comment: one figure, twelve Table
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