Duality-Violating 1/m_Q Effects in Heavy Quark Decay

I identify a source of \Lambda_{QCD}/m_Q corrections to the assumption of quark-hadron duality in the application of heavy quark methods to inclusive heavy quark decays. These corrections could substantially affect the accuracy of such methods in practical applications and in particular compromise their utility for the extraction of the Cabibbo-Kobayashi-Maskawa matrix element V_{cb}.Comment: 16 pages, 5 figures, an abbreviated version of hep-ph/9809279, the original JLAB-THY-98-03 ``Duality in Inclusive Semileptonic Heavy Quark Decay

Semileptonic Decay of BB-Meson into D∗∗D^{**} and the Bjorken Sum Rule

We study the semileptonic branching fraction of $B$-meson into higher resonance of charmed meson $D^{**}$ by using the Bjorken sum rule and the heavy quark effective theory(HQET). This sum rule and the current experiment of $B$-meson semileptonic decay into $D$ and $D^*$ predict that the branching ratio into $D^{**}l\nu_l$ is about 1.7\%. This predicted value is larger than the value obtained by the various theoretical hadron models based on the HQET.Comment: 10 pages, LaTex, to be published in Phys. Lett.

Semileptonic decays B→(π,ρ)eνB\to(\pi,\rho)e\nu in relativistic quark model

Quark model results for the $B\to \pi,\rho$ decays are analysed, making use of the dispersion formulation of the model: The form factors at $q^2>0$ are expressed as relativistic invariant double spectral representation over invariant masses of the initial and final mesons through their light--cone wave functions. The dependence of the results on the quark model parameters is studied. For various versions of the quark model the ranges $\Gamma(\bar B^0\to\pi^+e\bar\nu)=(7\pm2)\times10^{12}|V_{ub}|^2\; s^{-1}$, $\Gamma(\bar B^0\to\rho^+e\bar\nu)/\Gamma(\bar B^0\to\pi^+e\bar\nu)=1.45\pm0.1$, and $\Gamma_L/\Gamma_T=0.7\pm0.08$ are found. The effects of the constituent quark transition form factor are briefly discussed.Comment: latex, 8 pages, 2 figure

Flux Tube Zero-Point Motion, Hadronic Charge Radii, and Hybrid Meson Production Cross Sections

Flux tube zero-point motion produces quark displacements transverse to the flux tube which make significant contributions to hadronic charge radii. In heavy quark systems, these contributions can be related by Bjorken's sum rule to the rates for semileptonic decay to hybrid mesons. This connection can be generalized to other leptoproduction processes, where transverse contributions to elastic form factor slopes are related to the cross sections for the production of the associated hybrid states. I identify the flux tube overlap integral responsible for these effects as the strong QCD analogue of the Sudakov form factor of perturbative QCD.Comment: 16 pages, revised to clarify some points and to improve and correct the notation for the flux tube wave function

B Decay Studies at Cleo

Weak decays of heavy flavored hadrons are sensitive probes of several facets of the Standard Model. In particular the experimental study of B meson semileptonic decaysis starting to pin down the quark mixing parameters in the Cabibbo Kobayashi Maskawa matrix. In addition, some features of the non--perturbative regime of the strong interaction are probed by these decays. New results from the CLEO experiment at the CESR electron-positron collider, based on a data sample of up to 3.5 inverse femtobarn, provide crucial information on both of these aspects of heavy flavor phenomenology.Comment: 25 pages, 11 figures, Late

Heavy-quark binding and kinetic energies in heavy-light mesons and the constituent quark model

The spin-averaged binding energy and the hyperfine mass splitting of heavy-light mesons are investigated within the constituent quark model as a function of the inverse heavy-quark mass. It is shown that the so-called heavy-quark kinetic energy, -lambda1 / 2mQ, may differ remarkably from the non-relativistic expectation / 2mQ, thanks to relativistic effects in the effective interquark potential for heavy-light mesons, which may yield substantial 1 / mQ corrections to the heavy-quark static limit. The determination of the difference of the hadronic parameter lambda1 in the B(u(d)) and B(c) mesons can provide information about the strength of relativistic effects in the interquark interaction.Comment: to appear in Physics Letters

B -> K1 gamma and tests of factorization for two-body non leptonic Bdecays with axial-vector mesons

The large branching ratio for B-> K1 gamma recently measured at Belle implies a large B -> K1 transition form factor and large branching ratios for non leptonic B decays involving an axial-vector meson. In this paper we present an analysis of two-body B decays with an axial-vector meson in the final state using naive factorization and the B -> K1 form factors obtained from the measured radiative decays. We find that the predicted B -> J/psi K1 branching ratio is in agreement with experiment. We also suggest that the decay rates of B -> K1 pi, B -> a1 K and B -> b1 K could be used to test the factorization ansatz.Comment: 8 pages; 7 new references included and a comment on K2(1430) in the final state adde

K_{l 3} and \pi_{e 3} transition form factors

$K_{\ell 3}$ and $\pi_{e 3}$ transition form factors are calculated as an application of Dyson-Schwinger equations. The role of nonanalytic contributions to the quark--W-boson vertex is elucidated. A one-parameter model for this vertex provides a uniformly good description of these transitions, including the value of the scalar form factor of the kaon at the Callan-Treiman point. The $K_{\ell 3}$ form factors, $f_\pm^K$, are approximately linear on $t\in [m_e^2,m_\mu^2]$ and have approximately the same slope. $f_-^K(0)$ is a measure of the Euclidean constituent-quark mass ratio: $M^E_s/M^E_u$. In the isospin symmetric limit: $-f_+^\pi(0)= F_\pi(t)$, the electromagnetic pion form factor, and $f_-^\pi(t)\equiv 0$.Comment: 11 pages (incl. 3 figures), elsart.sty, epsf.st

Semileptonic B and D decays in the quark model

We predict the matrix elements and resulting electron spectra for semileptonic meson decays using the quark potential model. Particular attention is paid to the high-energy electron end-point region in B decay since it is crucial to a determination of the b→u weak mixing angle. It is argued that in this region the usual inclusive ("quark decay") calculations are unjustified and must be replaced by explicit sums over decays of the original meson into low-mass exclusive hadronic final states

Spin Dependence of Heavy Quark Fragmentation

We propose that the non-perturbative fragmentation functions describing the transition from a heavy quark to a heavy meson is proportional to the square of the produced meson wave function at the origin. We analyze the effects of this proposal on the number of pseudoscalar mesons compared to the number of vector mesons produced and find a good agreement with experimental data. Finally, we discuss further experimental checks for our hypothesis.Comment: 4 page