Related papers: Tree-level contributions to B -> Xs gamma
The upper limit of the branching ratio of the rare $\Xi_b^-\rightarrow \Xi^- \gamma$ decay is obtained as $BR(\Xi_b^-\rightarrow \Xi^- \gamma)<1.3\times10^{-4}$ by the LHCb. In the present work we study this decay within the light cone QCD…
We present an update on total and partial branching fractions and on CP asymmetries in the semi-inclusive decay B -> Xs l+l-. Further, we summarize our results on branching fractions and CP asymmetries for semi-inclusive and fully-inclusive…
The rare Higgs boson decay $H\to Z\gamma$ is forbidden at tree-level. In the Standard Model, it is loop-mediated through a $W$ boson or a heavy quark. We analytically compute the QCD correction to the heavy quark loop, confirming earlier…
Measurements of the rates for the hadronic decays B^+- -> pi K along with the CP-averaged B^+- -> pi^+- pi^0 branching ratio can be used to bound and extract the weak phase gamma=-arg(V_ub). Using preliminary CLEO data, we obtain the bounds…
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…
A method is described which, under the assumption of SU(3) symmetry, allows one to determine the angle gamma=Arg(Vub^*) of the unitarity triangle from time-independent measurements of the branching ratios for the decays B^+ -> pi^0 K^+ and…
A simple Pati-Salam SU(4) model with a low symmetry breaking scale of about 1000 TeV is presented. The analysis concentrates on calculating radiative corrections to tree-level mass relations for third generation fermions. The tree-level…
We compute for the first time the long-distance penguin contribution to the double radiative $B$-meson decays due to the purely hadronic operators acting with the electromagnetic current in the background soft-gluon field from first…
We study rare radiative leptonic decays $B_{(s)}\to e^+e^-\gamma$ and $B_{(s)}\to \mu^+\mu^-\gamma$ within relativistic quark model. In addition to previous analysis we give the estimations of the branching ratios for four values of the…
The rare decay $b\to ss\bar{d}$ is studied in a vector quark model by adding the contributions from exotic vector-like quarks. We find that the contribution from box diagrams amounts to $10^{-9}$ in the branching ratio, while the…
A useful inequality is obtained if charmless strange B decays are assumed to be dominated by the gluonic penguin diagram and the tree diagram contribution is small but not negligible. The penguin-tree interference contribution which is…
The semileptonic B-> Xu l nu decays allow a pretty clean determination of the CKM matrix element |Vub|. Nevertheless, the presence of weak-annihilation effects near the end-point of the q2 spectrum introduces uncertainties in the inclusive…
The branching ratio for the rare two-body B_s -> rho gamma decay is calculated using the factorization assumption. This transition is dominated by the annihilation diagrams and, in principle, prone to receiving substantial contributions…
The Higgs boson decay, H -> mu mubar gamma, is studied in the Standard Model at the tree and one-loop levels. It is shown that for Higgs boson masses above 110 GeV, the contribution to the radiative width from the one-loop level exceeds the…
In the Standard Model of electroweak interactions and in the tree--approximation we calculate the rate and branching ratio of the neutron radiative beta decay with one-real photon emission by taking into account the contributions of the…
The decay modes of the type $B \to \pi \, D $ are dynamically different. For the case $\bar{B_{d}^0} \to \pi^- D^{+} $ there is a substantial factorized contribution which dominates. In contrast, the decay mode $\bar{B_{d}^0} \to \pi^0…
The tree-level contributions to the rare decays B+ --> pi+ nu anti-nu, B+ --> K+ nu anti-nu, and B+ --> K*+ nu anti-nu are analyzed and compared to those occurring in K+ --> pi+ nu anti-nu, D+ --> pi+ nu anti-nu, and Ds+ --> pi+ nu anti-nu.…
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…
It is pointed out that decays of the type $B \to D \bar{D}$ have no factorizable contributions, unless at least one of the charmed mesons in the final state is a vector meson. The dominant contributions to the decay amplitudes arise from…
Theoretical predictions for B decay rates are rewritten in terms of the Upsilon meson mass instead of the b quark mass, using a modified perturbation expansion. The theoretical consistency is shown both at low and high orders. This method…