Related papers: Quark fragmentation into vector and pseudoscalar m…
We compute the differential and total rate of the semileptonic decay of polarized top-quarks $t\to \ell \nu_\ell + b{\rm jet} + {\rm jet}$ at next-to-leading order (NLO) in the QCD coupling with an off-shell intermediate $W$ boson. We…
Because quarks in hadronic states are subjected to strong QCD forces, it is not straight-forward to apply calculation obtained at the quark level to physical processes involving hadrons. In this paper we present a new approach to treat the…
We examine methods that have been proposed for determining the helicity structure of decays of new resonances to third generation quarks and/or leptons. We present analytical and semi-analytical predictions and assess the applicability of…
We develop a formalism for studying vector meson ($V$) photo-production at the proton ($p$) with polarized photons, $\vec\gamma p \to V p $, through an analysis of the decay distribution in the channel $V\to\pi^0\gamma$. We show that this…
We employ the relativistic constituent quark model to give a unified description of the leptonic and semileptonic decays of pseudoscalar mesons (\pi, K, D, D_s, B, B_s). The calculated leptonic decay constants and form factors are found to…
Semileptonic decays $D\to K,K^*,\pi,\rho$, $D_s\to \eta,\eta',\phi$, and $B\to D,D^*,\pi,\rho$ are analyzed within the dispersion formulation of the quark model. The form factors at timelike $q$ are derived by the analytical continuation…
The recent analyses of the following rare vector-vector decays of the B meson are presented: rho K*, omega K*, omega rho, omega omega, and omega phi charmless final states. The latest results indicate that the fraction of longitudinal…
We study the effects of the fourth generation of quarks on the total branching ratio and the lepton polarizations in $\bar{B}_{0}\rightarrow K_{0}^{\ast}(1430)l^{+}l^{-}$($l$ = $\mu $, $\tau $) decay. Taking fourth generation quark mass…
Studies of hadronic final states of $e^+e^-$ annihilations, observed at the Large Electron Positron Collider LEP at CERN, are reviewed. The topics included cover measurements of $\alpha_s$, hadronic event shapes and hadronisation studies,…
We analyze the effects of Scalar and Vector Leptoquarks on various observables in electron (positron) - proton deep inelastic scattering. In view of the future program of the HERA collider, with a high luminosity and also with polarization,…
Long-distance effects in exclusive rare semileptonic transitions B -> (K, K*) are analysed within a relativistic quark model. The meson transition form factors, describing the meson amplitudes of the effective weak Hamiltonian, are…
The observed $D^{**}$ mesons have $c\bar q$ flavor quantum numbers and spin-parity of the light degrees of freedom $s_\ell^{\pi_{\ell}} = 3/2^+$. In the $m_c \rightarrow \infty$ limit the spin of the charm quark is conserved and the $c…
Several aspects of the internal structure of pseudoscalar mesons, accessible through generalized parton distributions in their zero-skewness limit, are examined. These include electromagnetic and gravitational form factors related to charge…
We consider rare semileptonic decays of a heavy $D$-meson into a light vector meson in the framework of QCD factorization. In contrast to the corresponding $B$-meson decays, the naive factorization hypothesis does not even serve as a first…
Semileptonic decays of polarized $\tau$ leptons are investigated. The most general angular distribution of three meson final states ($\tau\rightarrow \pi\pi\nu,\,K\pi\nu,\, \pi\pi\pi\nu,\\ \,K\pi\pi\nu,\, KK\pi\nu,\, KKK\nu,\,…
All charmless $B \to PV\ell^+\nu_\ell$ ($P$ denotes the light pseudoscalar meson and $V$ denotes the vector meson) decays have not been experimentally observed to date, but some of them might be measured in the near future. The charmless $B…
The polarization measurement in the inclusive B decay provides us with a simple test of how much the long-distance final-state interaction takes place as the energy of the observed meson varies in the final state. We give the expectation of…
Masses of pseudoscalar and vector mesons, which are ground states of light or/and heavy quarks and antiquarks, have been calculated in the framework of an extended model of quasi-independent quarks with absolute uncertainties about 30 MeV.…
The form factors of the semileptonic $B$, $B_s$ and $B_c$ meson decays are calculated in the framework of the relativistic quark model based on the quasipotential approach in QCD. They are expressed through the overlap integrals of the…
Recently, the {\it Belle} and {\it BABAR} Collaborations published the single-inclusive electron-positron annihilation data at the center of mass energies ($\sqrt{s}$) of $10.52$ GeV and $10.54$ GeV, respectively. These new data offer one…