Related papers: $B_s (B_d) \to \gamma \nu \bar \nu $ }

Taking into account the gluon correction contributions to the correlation function, the form factors relevant to the rare $B_c \rar X \nu\bar{\nu}$ decays are calculated in the framework of the three point QCD sum rules, where $X$ stands…

The branching ratio of the rare decay B->X_s gamma provides potentially strong constraints on models beyond the Standard Model. Considering a general scenario with new heavy neutral gauge bosons, present in particular in Z' and gauge…

Employing dipole and exponential hadronic transition form factors and helicity analysis combined with the Lattice QCD input, we present a detailed study of the decays $B_s \to D_s^{(*)}\ell \nu_\ell$. $B_s \to D_s + P(V)$, where $P = \pi^+,…

Within QCD factorization approach, we employ the new results of form factors of $B_s \to \phi$ and calculate the branching fractions, CP asymmetries (CPAs) and polarization fractions of the decay modes $B_s \to \phi (\rho^0, \omega)$ in…

We determine the relative branching fractions of semileptonic B decays to charmed final states. The measurement is performed on the recoil from a fully reconstructed B meson in a sample of 362 million BBbar pairs collected at the…

We calculate the differential branching fraction, lepton forward-backward asymmetry and direct CP asymmetry for $B_{d,s}\to\gamma\ell\bar{\ell}$ decays with an energetic photon. We employ factorization methods, which result in rigorous…

We study the (tree-level) weak radiative decays of $B$ mesons. We present a numerical estimate for the inclusive $b \to X_c \gamma (\gamma)$ modes based on the free-quark decay. We then review what is known for the $B \to D^\star \gamma$…

b to s transitions are flavour-changing neutral current (FCNC) processes that play an important role in the search for physics beyond the Standard Model (SM). Contributions from virtual particles in the loop are predicted to deviate…

I discuss some theoretical aspects of rare $K$, $D$ and $B$ decays focusing mainly on their potential as tests of the one loop structure of the standard model. I concentrate on flavor changing neutral current processes and compare our…

We study the exclusive rare decay B -> K l(bar) l. We calculate the relevant form factors within a relativistic constituent quark model, for the first time without employing the impulse approximation. The calculated form factors are used to…

We discuss exclusive radiative decays in QCD factorization within the Standard Model. In particular, we consider the decays B -> V gamma, with a vector meson K* or rho in the final state, and the double radiative modes B_s -> gamma gamma…

To the leading order, the radiative leptonic decays $B_c \to \gamma \ell \bar \nu$ ($ \ell=e, \mu$) are studied carefully. In the study, a non-relativistic constituent quark model and the effective Lagrangian for the heavy flavour decays…

Semileptonic and leptonic B decays are analyzed in the framework of the relativistic quark model. Special attention is payed to the decays involving $\tau$ lepton. It is found that the calculated particular decay branching fractions are…

In these lectures we give, first, the model-independent analysis of the exclusive rare decays B -> K l(bar) l and B_c -> D(D*) l(bar) l with special emphasis on the cascade decay B_c -> D(*)(-> D pi) l(bar) l. We derive a four-fold angular…

Using the QCD sum rules technique we study several aspects of the phenomenology of the b-flavoured strange meson $B_s^0$. In particular, we evaluate the mass of the particle, the leptonic constant and the form factors of the decays…

We have studied the decay $\bar{B} \to D\ell\bar{\nu}$, where $\ell=e or \mu$. From a fit to the differential decay rate $d\Gamma/dw$ we measure the rate normalization ${\cal F}_D(1)|V_{cb}|$ and form factor slope $\hat{\rho}^2_D$, and,…

We investigate the decay of $\Lambda_b\to\Lambda\nu\bar{\nu}$ with the polarized baryons of $\Lambda_b$ and $\Lambda$. With the most general hadronic form factors, we first study the decay branching ratio and then derive the longitudinal,…

The rare decay $B^+ \to D_s^+ \phi $ can occur only via annihilation type diagram in the standard model. The small branching ratio predicted in the standard model makes this channel sensitive to new physics contributions. We analyze this…

Applying the perturbative QCD ( PQCD ) method, we study the decay $B_c\rightarrow D_s^*\gamma$ in the standard model and multiscale walking technicolor model. In the SM, we find that the contribution of weak annihilation is more important…

Using the most general model independent form of the effective Hamiltonian the rare decay B_s->nu nu gamma is studied. The sensitivity of the photon energy distribution and branching ratio to new Wilson coefficients are investigated.