778 research outputs found
New analysis of semileptonic B decays in the relativistic quark model
We present the new analysis of the semileptonic B decays in the framework of
the relativistic quark model based on the quasipotential approach. Decays both
to heavy D^{(*)} and light \pi(\rho) mesons are considered. All relativistic
effects are systematically taken into account including contributions of the
negative-energy states and the wave function transformation from the rest to
moving reference frame. For heavy-to-heavy transitions the heavy quark
expansion is applied. Leading and subleading Isgur-Wise functions are
determined as the overlap integrals of initial and final meson wave functions.
For heavy-to-light transitions the explicit relativistic expressions are used
to determine the dependence of the form factors on the momentum transfer
squared. Such treatment significantly reduces theoretical uncertainties and
increases reliability of obtained predictions. All results for form factors,
partial and total decay rates agree well with recent experimental data and
unquenched lattice calculations. From this comparison we find the following
values of the Cabibbo-Kobayashi-Maskawa matrix elements:
|V_{cb}|=(3.85\pm0.15\pm 0.20)*10^{-2} and
|V_{ub}|=(3.82\pm0.20\pm0.20)*10^{-3}, where the first error is experimental
and the second one is theoretical.Comment: 25 pages, 11 figure
Heavy quark potential and mass spectra of heavy mesons
The relativistic quark model is presented. The quark-antiquark potential for
the Schroedinger-like equation is constructed with the account of retardation
effects and one-loop radiative corrections. It consists of the one-gluon
exchange part and the confining part which is the mixture of the Lorentz scalar
and Lorentz vector contributions. The latter contains both the Dirac and Pauli
terms. In the v^2/c^2 approximation the mass spectra of heavy quarkonia
(charmonium and bottomonium) are calculated in good agreement with experiment.
In the case of heavy-light mesons (B and D) the light quark is treated
completely relativistically and only the expansion in the inverse heavy quark
mass is used. The mass spectra of the ground and excited states of D, D_s, B,
B_s mesons are calculated. They exhibit some features of the so-called ``level
inversion''. The obtained results are generally in accord with experimental
data. Still there exist some discrepancies between measurements of different
collaborations.Comment: 10 pages, plenary talk at the IXth International Conference on Hadron
Spectroscopy (August 25-September 1, 2001) - HADRON 2001, Protvino, Russi
Heavy quarkonium hyperfine structure and leptonic decays
The relation between the hyperfine structure and leptonic decay rates of
heavy quarkonia is considered with the account of relativistic and radiative
corrections. The calculated decay rates agree well with the available
experimental data, while the predicted eta_c(2S) mass is significantly smaller
than the value measured recently by the Belle and BaBar Collaborations.Comment: Invited talk at the XXIII Physics in Collisions Conference (PIC03),
Zeuthen, Germany, June 2003, 3 pages, LaTeX. PSN FRAP0
Two-photon decay rates of heavy quarkonia in the relativistic quark model
Two-photon decay rates of pseudoscalar, scalar and tensor states of
charmonium and bottomonium are calculated in the framework of the relativistic
quark model. Both relativistic effects and one-loop radiative corrections are
taken into account. The obtained results are compared with other theoretical
predictions and available experimental data.Comment: 7 pages, 1 figur
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