82,272 research outputs found
The NLO QCD Corrections to Meson Production in Decays
The decay width of to meson is evaluated at the next-to-leading
order(NLO) accuracy in strong interaction. Numerical calculation shows that the
NLO correction to this process is remarkable. The quantum
chromodynamics(QCD)renormalization scale dependence of the results is obviously
depressed, and hence the uncertainties lying in the leading order calculation
are reduced.Comment: 14 pages, 7 figures; references added; expressions and typos ammende
Estimating Form Factors of and their Applications to Semi-leptonic and Non-leptonic Decays
and weak transition
form factors are estimated for the whole physical region with a method based on
an instantaneous approximated Mandelstam formulation of transition matrix
elements and the instantaneous Bethe-Salpeter equation. We apply the estimated
form factors to branching ratios, CP asymmetries and polarization fractions of
non-leptonic decays within the factorization approximation. And we study the
non-factorizable effects and annihilation contributions with the perturbative
QCD approach. The branching ratios of semi-leptonic decays are also evaluated. We show that the calculated
decay rates agree well with the available experimental data. The longitudinal
polarization fraction of decays are when
denotes a light meson, and are when denotes a
() meson.Comment: Final version published in J Phys. G 39 (2012) 045002 (Title also
changed
Production of the -Wave Excited -States through the Boson Decays
In Ref.[7],we have dealt with the production of the two color-singlet
-wave -quarkonium states and
through the boson decays. As an
important sequential work, we make a further discussion on the production of
the more complicated -wave excited -quarkonium states, i.e.
and (with
). More over, we also calculate the channel with the two color-octet
quarkonium states and , whose contributions to the decay width maybe at the same order of
magnitude as that of the color-singlet -wave states according to the naive
nonrelativistic quantum chromodynamics scaling rules. The -wave states shall
provide sizable contributions to the production, whose decay width is
about 20% of the total decay width . After summing up all
the mentioned -quarkonium states' contributions, we obtain
KeV, where the errors are caused
by the main uncertainty sources.Comment: 8 pages, 5 figures and 2 tables. basic formulae in the appendix are
cut off to match the published version, which can be found in v1. to be
published in Eur.Phys.J.
Boson Decays to Meson and Its Uncertainties
The programming new collider with high luminosity shall provide
another useful platform to study the properties of the doubly heavy meson
in addition to the hadronic colliders as LHC and TEVATRON. Under the `New Trace
Amplitude Approach', we calculate the production of the spin-singlet and
the spin-triplet mesons through the boson decays, where
uncertainties for the production are also discussed. Our results show
KeV and
KeV, where the errors are caused by
varying and within their reasonable regions.Comment: 11 pages, 5 figures, 2 tables. To be published in Eur.Phys.J.
An asymptotic solution of conical shells of constant thickness Progress report no. 6
Asymptotic solution of thin walled conical shell of revolution under lateral stres
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
Fitting Precision Electroweak Data with Exotic Heavy Quarks
The 1999 precision electroweak data from LEP and SLC persist in showing some
slight discrepancies from the assumed standard model, mostly regarding and
quarks. We show how their mixing with exotic heavy quarks could result in a
more consistent fit of all the data, including two unconventional
interpretations of the top quark.Comment: 7 pages, no figure, 2 typos corrected, 1 reference update
The magnetic dipole transitions in the binding system
The magnetic dipole transitions between the vector mesons and their
relevant pseudoscalar mesons (, , , ,
and etc, the binding states of system) of
the family are interesting. To see the `hyperfine' splitting due to
spin-spin interaction is an important topic for understanding the spin-spin
interaction and the spectrum of the the binding system. The
knowledge about the magnetic dipole transitions is also very useful for
identifying the vector boson mesons experimentally, whose masses are
just slightly above the masses of their relevant pseudoscalar mesons
accordingly. Considering the possibility to observe the vector mesons via the
transitions at factory and the potentially usages of the theoretical
estimate on the transitions, we fucus our efforts on calculating the magnetic
dipole transitions, i.e. precisely to calculate the rates for the transitions
such as decays and , and particularly
work in the Behte-Salpeter framework. In the estimate, as a typical example, we
carefully investigate the dependance of the rate
on the mass difference as well.Comment: 10 pages, 2 figures, 1 tabl
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