Related papers: Constraining $\lambda_{B_s}$ by $B_s\to \gamma^*$ …
Long distance effects are studied in the rare exclusive semileptonic $B_{(d,s)}\to V \ell^+ \ell^-$ decays, where $V$ denotes a $K^*$ or $\phi$ meson. The form factors, which describe the meson transition amplitudes in the effective…
We describe the calculation of the $B\rightarrow \pi$ hadronic matrix element from operator product expansion near the light-cone in QCD. In the resulting sum rules, the form factors $f^+$ and $F_0$ determining this matrix element are…
The electromagnetic form factors G_E(q^2), G_M(q^2), and G_Q(q^2), charge radii, magnetic and quadrupole moments, and decay widths of the light vector mesons rho^+, K^{*+} and K^{*0} are calculated in a Lorentz-covariant, Dyson-Schwinger…
The leptonic radiative decay $B \to \gamma l\nu$ is of great importance in the determination of $B$ meson wave functions, and evaluating the form factors $ F_{V,A}$ are the essential problem on the study of this channel. We computed…
Soft-QCD effects of quark-level form factors in $\gamma\gamma$ decay of $B_s$-mesons via $D{\bar D}$ intermediate states, suggested by Ellis et al, are examined in the "Salpeter" model [reinterpreted in terms of the Markov-Yukawa…
A consistent treatment of $B\rightarrow \pi l \nu$ decay is given on the light-front. The $B$ to $\pi$ transition form factors are calculated in the entire physical range of momentum transfer for the first time. The valence-quark…
Within the framework of QCD light-cone sum rules (LCSR), we calculate the form factor for $B{\to}D l\tilde{\nu}$ transitions with chiral current correlator. The resulting form factor depends on the distribution amplitude(DA) of the…
In this article, we study the $B \to K^*_2(1430)$, $a_2(1320)$, $f_2(1270)$ form-factors with the light-cone QCD sum rules, where the $B$-meson light-cone distribution amplitudes are used. In calculations, we observe that the line-shapes of…
In this work, the transition form factors of the semileptonic decays of $B_{(s)}$ to the light scalar mesons with masses close to $1.5~\rm{GeV}$ such as $K_0^*(1430), a_0(1450)$, and $f_0(1500)$ are calculated in the framework of the…
We present the first analytic ${\cal O}(\alpha_s)$-computation at twist-$1$,$2$ of the $\bar B_{u,d,s} \to \gamma$ form factors within the framework of sum rules on the light-cone. These form factors describe the charged decay $\bar B_u \to…
We use the AdS/QCD distribution amplitudes for light mesons to calculate the transition form factors for B to $\rho$, $K^*$ decays. These form factors are then utilized to make predictions for the semileptonic $B\to\rho\ell\nu$ and…
We study photon--meson transition form factors $\gamma^*(Q^2)\gamma \to \pi^0,\eta,\eta'$ at low and moderately high virtualities $Q^2$ of one of the photons, the second photon being real. For the description of the form factor at low…
A lattice calculation of the form factors that determine the ``hadronization ratios'', such as $R_{K^*}$ and $R_{\phi}$, where $R_{K^*} \equiv [\Gamma ($B \to K^* \gamma$)/\Gamma(b \to s \gamma)]$, is presented in the quenched…
We calculate the heavy-to-light form factors in the relativistic quark model with heavy infrapropagators. Their q^2-dependence in the physical region is defined by two parameters: the "infrared" parameter \nu characterizing the infrared…
We analyse various $U(1)_{EM}$ form factors of mesons at strong coupling in an $\mathcal{N}=2$ flavored version of $\mathcal{N}=4$ $SYM$ which becomes conformal in the UV. The quark mass breaks the conformal symmetry in the IR and generates…
In this paper, we calculate the vector, axial-vector and tensor form factors of $P\to T$ transition within the standard light-front~(SLF) and covariant light-front~(CLF) quark models~(QMs). The self-consistency and Lorentz covariance of CLF…
This article is devoted to calculating the form factors of $B_c \to D^{*}$, $B_c \to D$, $B_c \to D_s^{*}$ and $B_c \to D_s$ transitions in the framework of three-point QCD sum rules. At the QCD side, the contributions of…
We present $B_q\to\rho$, $B_q\to\omega$, $B_q\to K^*$, $B_s\to K^*$ and $B_s\to \phi$ form factors from light-cone sum rules (LCSR) at $\mathcal{O}(\alpha_s)$ for twist-2 and 3 and $\mathcal{O}(\alpha_s^0)$ for twist-4 with updated hadronic…
Employing the standard hard-scattering approach and the running coupling method we calculate a class of power-suppressed corrections $\sim 1/Q^{2n},n=1,2,3,...$ to the electromagnetic $\pi^0\gamma$ transition form factor (FF)…
We discuss the evaluation of the transition form factor (TFF) $F^{\gamma*\gamma\pi^0}(Q^2)$ by means of QCD theory and by state-space reconstruction from topological data analysis. We first calculate this quantity in terms of quark-gluon…