Related papers: Radiative Leptonic B Decays in the Light Front Mod…
We analyze $K_L$ lepton pair decays of $K_L \to l^+\l^-\gamma$ and $K_L \to l^+l^-l'^+l'^-$ $(l, l'=e, \mu)$ within the framework of the light-front QCD approach (LFQA). With the $K_L \to \gamma^* \gamma^*$ form factors evaluated in a model…
In this paper, I study the branching ratio of the rare radiative decay $B_s \to \nu \bar{\nu} \gamma$ in the framework of the Fourth-Generation Standard Model and the Two-Higgs-Doublet Model. It is shown that this quantity is a very…
In the $\rm SU(3)_F$ symmetry limit, using two- and three-particle distribution amplitudes of $B^{\pm}$-meson for $B_s$, the transition form factors of semileptonic $B_{s}\to K_{0}^*(1430)$ decays are calculated in the framework of the…
The branchings fractions of the rare $B_s$ decays are calculated in the framework of the QCD-motivated relativistic quark model. The form factors of the weak $B_s$ transitions to light mesons are expressed through the overlap integral of…
Using dispersive methods, we study the $B \to \gamma^*$ form factors underlying the decay $B^- \to \ell^- \bar{\nu}_\ell \ell^{\prime-} \ell^{\prime+}$. We discuss the ambiguity that arises from a separation of the full $B^- \to \ell^-…
We investigate the exclusive semileptonic $B_c\to (D,\eta_c,B,B_s)\ell\nu_\ell$, $\eta_b\to B_c\ell\nu_\ell$($\ell=e,\mu,\tau$) decays using the light-front quark model constrained by the variational principle for the QCD motivated…
The photoleptonic decay $B^-\to \gamma \ell^-\bar{\nu}$ is the simplest low-energy process that probes the substructure of the $B$ meson, making it an excellent candidate to determine the parameters of $B$-meson light-cone distribution…
Motivated by the first search for the rare charged-current $B$ decay to four leptons, $\ell \bar{\nu}_\ell \ell^{(\prime)} \bar{\ell}^{(\prime)}$, we calculate the decay amplitude with factorization methods. We obtain the $B\to \gamma^*$…
We analyze the semileptonic (B_c -> B_u* l+ l-) decay in the frame work of the Standard Model. We calculate the (B_c) to (B_u*) transition form factors in QCD sum rules. Analytical expressions for the spectral densities and gluon…
We study the decays of $\tau^- \to \nu_{\tau} P^-\gamma (P=\pi^-, K^-)$ in the light front quark model. We calculate the form factors and use them to evaluate the decay widths. We find that, in the standard model, the decay widths are…
We study the radiative leptonic $B_c\to \gamma\ell\bar\nu$ decays in the nonrelativistic QCD effective field theory, and consider a fast-moving photon. As a result the interactions with the heavy quarks can be integrated out, and thus we…
We extend the Standard Model (SM) analysis of Ref. [1], which was limited to light leptons in the final state, to the semileptonic $B \to D^* \tau \nu_\tau$ decay. By using quantities that can be analised without the knowledge of $\vert…
The measured $\bar{B}\to D^{(*)} l \bar\nu$ decay rates for light leptons ($l=e,\mu$) constrain all $\bar{B}\to D^{(*)}$ semileptonic form factors, by including both the leading and ${\cal O}(\Lambda_{\text{QCD}}/m_{c,b})$ subleading…
We investigate the exclusive rare $B_c\to D_{(s)}\nu_{\ell}\bar{\nu_{\ell}}$ and $B\to D_{(s)}\ell^+\ell^-$ ($\ell=e,\mu,\tau$) decays within the standard model and the light-front quark model constrained by the variational principle for…
Semileptonic $\Lambda_b$ decays are investigated in the framework of the relativistic quark model based on the quasipotential approach and the quark-diquark picture of baryons. The decay form factors are expressed through the overlap…
We present a search for the radiative leptonic decays B+ -> e+ nu gamma and B+ -> mu+ nu gamma using data collected by the BABAR detector at the PEP-II B factory. We fully reconstruct the hadronic decay of one of the B mesons in Upsilon(4S)…
The decay $K_L \to \gamma \nu \bar{\nu}$ is analyzed within the standard model. Short-distance contributions are found to dominate, yielding a branching ratio of $\sim 0.7 \times 10^{-11}$. We examine the possibility that non-standard model…
An explicit relativistic light-front quark model is presented which gives the momentum transfer dependent form factors of weak hadronic currents among heavy pseudoscalar and vector mesons in the whole accessible kinematic region $ 0\leq q^2…
We study transition form factors for radiative and rare semi-leptonic B-meson decays into light pseudoscalar or vector mesons, combining theoretical constraints and phenomenological information from Lattice QCD, light-cone sum rules, and…
Semi-leptonic $B_s \to K \ell \nu$ and $B_s \to D_s \ell \nu$ decays provide an alternative $b$-decay channel to determine the CKM matrix elements $|V_{ub}|$ and $|V_{cb}|$ or to obtain $R$-ratios to investigate lepton flavor universality…