680 research outputs found
Higher Order Power Corrections in Inclusive B Decays
We discuss order 1/m_b^4 and 1/m_b^5 corrections in inclusive semileptonic
decay of a meson. We identify relevant hadronic matrix elements of
dimension seven and eight and estimate them using the ground-state saturation
approximation. Within this approach the effects on the integrated rate and on
kinematic moments are estimated. The overall relative shift in V_{cb} turns out
about +0.4% as applied to the existing fits. Similar estimates are presented
for B -> X_s+\gamma decays.Comment: 30 pages, 16 figure
Analyticity Properties and Unitarity Constraints of Heavy Meson Form Factors
We derive new bounds on the b-number form factor of the B meson.
(Revised version of hep-ph/9306214).Comment: 22 page
decays in the Left-Right Symmetric Model
We consider decays in the Left-Right Symmetric Model. Values
of observables sensitive to chiral structure such as the polarization
in the decays and the mixing-induced CP
asymmetries in the decays can deviate in the LRSM
significantly from the SM values. The combined analysis of and
as well as can be used to determine the
model parameters.Comment: 16 pages with 7 figures, Version to be published in PR
Quark-binding effects in inclusive decays of heavy mesons
We present a new approach to the analysis of quark-binding effects in
inclusive decays of heavy mesons within the relativistic dispersion quark
model. Various differential distributions, such as electron energy spectrum,
- and -distributions, are calculated in terms of the meson soft
wave function which also determines long-distance effects in exclusive
transition form factors. Using the quark-model parameters and the meson
wave function previously determined from the description of the exclusive transitions within the same dispersion approach, we provide numerical
results on various distributions in the inclusive decays.Comment: revtex, 18 pages, preprint HD-THEP-99-50 (Heidelberg) and
RM3-TH/99-13 (Roma
A diquark model for baryons containing one heavy quark
We present a phenomenological ansatz for coupling a heavy quark with two
light quarks to form a heavy baryon. The heavy quark is treated in the heavy
mass limit, and the light quark dynamics is approximated by propagating scalar
and axial vector 'diquarks'. The resulting effective lagrangian, which
incorporates heavy quark and chiral symmetry, describes interactions of heavy
baryons with Goldstone bosons in the low energy region. As an application, the
Isgur--Wise form factors are estimated.Comment: 9 pages + 8 figures, both as uuencoded PS, discussion of Bjorken
limit (1 par + 1 fig) added, to appear in Z.Phys.
B-> D* zero-recoil formfactor and the heavy quark expansion in QCD: a systematic study
We present a QCD analysis of heavy quark mesons focussing on the B -> D*
formfactor at zero recoil, F_D*(1). An advanced treatment of the perturbative
corrections in the Wilsonian approach is presented. We estimate the
higher-order power corrections to the OPE sum rule and describe a refined
analysis of the nonresonant continuum contribution. In the framework of a
model-independent approach, we show that the inelastic contribution in the
phenomenological part of the OPE is related to the mQ-dependence of the
hyperfine splitting and conclude that the former is large, lowering the
prediction for F_D*(1) down to about 0.86. This likewise implies an enhanced
yield of radial and D-wave charm excitations in semileptonic B decays and
alleviates the problem with the inclusive yield of the wide excited states. We
also apply the approach to the expectation values of dimension 7 and 8 local
operators and to a few other issues in the heavy quark expansion.Comment: 70 pages, 13 figure
Isgur-Wise Functions from the Mit Bag Model
The Isgur-Wise functions for the ground state to ground state semileptonic
decays involving transitions are calculated from the
(modified) MIT bag model. It is checked that the results for the decays
and agree well with experiment. Predictions for the decays , and are given
and discussed.Comment: 12 pages (3 figures available upon request), LaTeX, TPJU - 9/9
The Isgur-Wise function in a relativistic model for system
We use the Dirac equation with a ``(asymptotically free) Coulomb + (Lorentz
scalar) linear '' potential to estimate the light quark wavefunction for mesons in the limit . We use these wavefunctions to
calculate the Isgur-Wise function for orbital and radial
ground states in the phenomenologically interesting range . We find a simple expression for the zero-recoil slope, , where is the energy eigenvalue
of the light quark, which can be identified with the parameter
of the Heavy Quark Effective Theory. This result implies an upper bound of
for the slope . Also, because for a very light quark the size of the meson is determined mainly by the
``confining'' term in the potential , the shape of
is seen to be mostly sensitive to the dimensionless
ratio . We present results for the ranges of
parameters , and
light quark masses and compare to existing
experimental data and other theoretical estimates. Fits to the data give:
,
and [ARGUS
'93]; , and
[CLEO '93]; ${\bar\Lambda_{u,d}}^2/Comment: 22 pages, Latex, 4 figures (not included) available by fax or via
email upon reques
Spectroscopy of Heavy Mesons Expanded in 1/m_Q
Operating just once with the naive Foldy-Wouthuysen-Tani transformation on
the relativistic Fermi-Yang equation for bound states described by
the semi-relativistic Hamiltonian which includes Coulomb-like as well as
confining scalar potentials, we have calculated heavy meson mass spectra of D
and B together with higher spin states. Based on the formulation recently
proposed, their masses and wave functions are expanded up to the second order
in with a heavy quark mass and the lowest order equation is
examined carefully to obtain a complete set of eigenfunctions for the
Schr\"odinger equation. Heavy quark effective theory parameters, ,
, and , are also determined at the first and second order
in .Comment: 49 pages, 5 epsf figure
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