相关论文: Uncertainties from Long Range Effects in $B \to K^…

We report the results of the first computation related to the study of the spectator effects in the rare decay mode $B\to K \gamma \gamma $ within the framework of Standard Model. It is found that the account of these effects results in the…

The current status of some methods to determine the weak phase $\gamma$ of the Cabibbo-Kobayashi-Maskawa (CKM) matrix element $V^*_{ub}$ using B decays is discussed, and comments are made on accuracy achievable in the next few years.

The extraction of the $B\to K^*$ transition form factors from lattice data is studied, applying non-relativistic effective field theory in a finite volume. The possible mixing of $\pi K$ and $\eta K$ states is taken into account. The…

We argue that the factorizable $c\bar c$ long- and short-distance contributions to the $B\to K^*\gamma$ amplitude vanish, separately, if defined in a gauge-invariant way. Therefore, the $c\bar c$ states contribute to the radiative decay…

We investigate the effects of photon radiation on deep-inelastic $\re\gamma$ scattering. Depending on the set of variables chosen, we find appreciable effects in the kinematic region accessible at LEP2. Convenient analytic results for…

We reanalyze the $B\to M$ tensor form factors in a covariant light-front quark model, where $M$ represents a vector meson $V$, an axial-vector meson $A$, or a tensor meson $T$. The treatment of masses and mixing angles in the $K_{1A,1B}$…

I stress the fact that a complete study of possible New Physics effects in the $Z \rightarrow b\bar{b}$ vertex requires a combined analysis of the ratio $R_b= \Gamma(Z \rightarrow b\bar{b})/ \Gamma(Z \rightarrow hadrons)$ and the…

The B -> K^* gamma branching fraction is predicted using heavy quark spin symmetry at large recoil to relate the tensor and (axial-)vector form factors, using heavy quark flavor symmetry to relate the B decay form factors to the measured D…

We analyse the $\overline B_s^0\to K^+l^-\bar \nu$ and $\overline B_s^0\to K^{*+}(\to K\pi) \ell^-\bar \nu$ decays that are valuable for extracting the CKM matrix element $|V_{ub}|$. We calculate the differential and integrated partial…

I overview the hadronic input for the exclusive flavour-changing neutral-current $B$-decays with a vector ($V=K^*,\rho$) or pseudoscalar ($P=K,\pi$) meson in the final state. After presenting the current status of $B\to P,V$ form factors, I…

We discuss some selected topics in rare B decays in the context of the standard model and compare theoretical estimates with available data. Salient features of the perturbative-QCD and power corrections in the decay rate for $B \to X_s +…

Within the framework of chiral effective field theory, we study various electromagnetic processes with light vector resonances: $K^{\ast}(892)\to K\gamma$, $e^{+}e^{-}\to K^{\ast}(892)K $ and the $\omega\pi\gamma^\ast$ form factors. With…

We present a detailed analysis of the $D \to V \gamma $ transitions, using a model which combines heavy quark effective theory and the chiral Lagrangian approach and includes symmetry breaking. We notice that in addition to the previously…

We investigate the rare decay $\Lambda_b \to \Lambda \gamma$ which receives both short and long distance contributions. We estimate the long distance contributions and find them very small. The form factors are obtained from $\Lambda_c \to…

The long-distance contribution via the two-photon intermediate state to the forward-backward asymmetries in decays K+ --> pi+ l+ l- (l=e and mu) has been studied within the standard model. In order to evaluate the dispersive part of the K+…

The short-distance contribution due to the $c\to u\gamma$ penguin as well as long-distance contributions are considered in an analysis of $D\to V\gamma$ decays, the latter being dominant. The matrix elements for nine $D\to V\gamma$…

Many of the important conclusions about Gamma-Ray Bursts follow from the distributions of various quantities such as peak flux or duration. We show that for astrophysical transients such as bursts, multiple selection thresholds can lead to…

To leading order in $\alpha_s$, we evaluate the leading and non-leading $1/M_b$ corrections to the $B^*B\pi$ and $B^*B\gamma$ couplings using QCD spectral moment sum rules in the full theory. We find that, for large $M_b$ and contrary to…

We suppose that there is new physics (NP) in b -> s transitions, and examine its effect on the angular distribution of B_q^0 -> V_1 V_2 (q=d,s), where V_{1,2} are vector mesons. We find that, in the presence of such NP, the formulae…

We consider the long distance contributions to inclusive penguin processes through processes like $b\rightarrow s V$ and $b\rightarrow d V$ where $V$ are $^3S_1(c\bar c)$ states $\psi_i$ in the former case and include $\rho$, $\omega$ for…