8,188 research outputs found
Charge radii of light and heavy mesons
We calculate the electromagnetic (EM) form factors of the pseudoscalar mesons
in the light-front framework. Specifically, these form factors are extracted
from the relevant matrix elements directly, instead of choosing the Breit
frame. The results show that the charge radius of the meson is related to both
the first and second longitudinal momentum square derivatives of the momentum
distribution function. The static properties of the EM form factors and the
heavy quark symmetry of the charge radii are checked analytically in the heavy
quark limit. In addition, we use the Gaussia-type wavefunction to obtain the
numerical results.Comment: 14 pages, 2 figures, some sections added in text. To appear in
Eur.Phys.J.
Three symmetry breakings in strong and radiative decays of strange heavy mesons
In this paper, we investigate three symmetry breaking effects in strong and
radiative decays of strange heavy mesons. We study 1/m_Q corrections within the
heavy quark effect theory, as well as SU(3) and SU(2) symmetry breakings
induced by light quark mass differences and the \eta-\pi mixing vertex. These
effects are studied in a covariant model. The numerical results show that the
1/m_Q corrections of the coupling constants are consistent with \alpha_s
\Lambda_{QCD}/m_Q. The SU(3) symmetry violating effect of the strong coupling
constant is obviously larger than that of the magnetic coupling constant. The
value of the \eta-\pi mixing vertex has some changes because of the renewed
data. As compared with the other theoretical calculations and the experimental
data, our radiative decay rates are much larger than those of the other
theoretical methods, except for \chiPT; however, our branching ratios are close
to the experimental data.Comment: 26 pages, 9 figures; several changes made for further clarity; one
figure and some references added; results and conclusions unchanged, version
to appear in Eur. Phys. J. C. arXiv admin note: substantial text overlap with
arXiv:1401.391
Analyses of decay constants and light-cone distribution amplitudes for s-wave heavy meson
In this paper, a study of light-cone distribution amplitudes (LCDAs) for
-wave heavy meson are presented in both general and heavy quark frameworks.
Within the light-front approach, the leading twist light-cone distribution
amplitudes, , and their relevant decay constants of heavy
pseudoscalar and vector mesons, , have simple relations. These relations
can be further simplified when the heavy quark limit is taken into
consideration. After fixing the parameters that appear in both Gaussian and
power-law wave functions, the corresponding decay constants are calculated and
compared with those of other theoretical approaches. The curves and the first
six -moments of are plotted and estimated. A conclusion is
drawn from these results: Even though the values of the decay constants of the
distinct mesons are almost equal, the curves of their LCDAs may have quite
large differences, and vice versa. Additionally, in the heavy quark limit, the
leading twist LCDAs, and , are compared
with the -meson LCDAs, , suggested by the other theoretical
groups.Comment: 25 pages, 3 figures, 4 tables, some typos are corrected, version to
be published in Phys. Rev.
Two-photon and two-gluon decays of p-wave heavy quarkonium using a covariant light-front approach
In this paper, a study of two-photon and two-gluon decays in the context of
p-wave heavy quarkonia is presented. Within the covariant light-front
framework, the annihilation rates of scalar and tensor quarkonium states are
derived. In the absence of free parameters in this case, the results for the
charmonium decay widths are consistent with the experimental data. However, in
comparison to other theoretical calculations, there are large discrepancies in
our results regarding bottomonia.Comment: 19 pages, 3 figures, 3 tables, some typos are corrected, version to
be published in Phys. Rev.
Strong and radiative decays of heavy mesons in a covariant model
In this paper, we investigate symmetry breaking effects in strong and
radiative decays of heavy mesons. We study corrections within the heavy
quark effective theory. These effects are studied in a covariant model for
heavy mesons. The numerical results are consistent with the experimental data
and some other theoretical calculations. These provide a vote of confidence for
the validity of this covariant model.Comment: 35 pages, 7 figures, minor modifications and some references added,
accepted for publication in JHE
A Study of the Impacts of the Panama Canal Expansion on the U.S. Northeast Ports and Strategy of the Port of Boston
When it is completed in 2016, the Panama Canal expansion will increase the trade volume and route from Asia to the United States as well as the competition amongst all U.S. ports, creating economic impacts in several areas. East Coast ports will be affected the most due to investments in harbor expansion projects and rise in cargo traffic and imports. The expansion will provide access for the Post-Panamax ships to the East Coast ports. These ships can increase cargo size from 5,000 up to 13,000 TEU’s (twenty-foot equivalent unit). It is estimated that 20-25% of import traffic will shift to the East Coast (Regional, 2013). Larger ships will be able to travel faster and carry heavier loads directly to the East Coast ports, thus eliminating the West Coast stop and reducing train transportation of cargo to the East Coast. In this study there will be a comparison of the economic impacts that the expansion of the Panama Canal creates between the Port of Boston and other major Northeast Ports, specially the Port of Baltimore, the Port of Norfolk and the Port of New York and New Jersey. This paper will evaluate the opportunities and strategies for the Port of Boston, utilizing business models of Strategy Canvas and Four Actions Framework in combination with the Port Choice Model
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