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

Rescattering effects can modify the dependence on the weak phase $\gamma = -{\rm Arg}(V^*_{ub}V_{ud}/V^*_{cb} V_{cd})$ of the ratio of rates for $B^{\pm} \to K \pi^\pm$ and $B \to K^\pm \pi^\mp$. A test for these effects based on the…

We study the decay of the neutral B meson to $K^* \gamma \gamma$ within the framework of the Standard Model, including long distance contributions.

We evaluate the branching ratios of the radiative decays $B \to K^* \gamma $, and $B \to K_1 \gamma $ in the framework of three-point function QCD sum rules. We find: $ \Gamma(B \to K^* \gamma) / \Gamma(b \to s \gamma) = 0.17 \pm 0.05$ and…

Measurements of polarization fractions in $B \to VV$ transitions, with $V$ a light vector meson, show that the longitudinal amplitude dominates in $B^0 \to \rho^+ \rho^-$, $B^+ \to \rho^+ \rho^0$, and $B^+ \to \rho^0 K^{*+}$ decays and not…

We use existing measurements of $D^-\to K^{\ast0}\rho^-$ and $B\to \psi+K^\ast$, coupled with flavor independence of QCD, and with vector meson dominance to show that long distance contributions to $B\to \rho +\gamma$ are potentially very…

Working in a perturbative QCD model approach, we obtain the essential form factor of the radiative transition $B \rightarrow V^{*} \gamma$ and estimate the branching ratio $BR(B \rightarrow K^{*} \gamma)$. The results are determined by a…

We re-examine the possibility to measure the photon polarization in $B \to K^*\gamma$ decays, via decays in which the photon subsequently undergoes nuclear conversion to a lepton pair. We obtain compact expressions for the full…

The long distance vector-meson-dominance (VMD) effects on the weak radiative decays $\bb\to\rho\gamma$ and $\bb^0\to D^{*0}\gamma$ are studied. For $\bb\to\rho\gamma$ decays, the VMD contribution is $(10-20)\%$ of the short-distance penguin…

A phenomenological analysis of $K\to \pi\pi\gamma$ ($K_L\to\pi^+\pi^-\gamma$ and $K^+\to\pi^+\pi^0\gamma$) with the direct emission photon is carried out beyond the leading order in the chiral perturbation theory. We show that the…

We calculate the branching ratios of $B\to K_1\gamma$ at next-to-leading order (NLO) of $\alpha_s$ where $K_1$ is the orbitally excited axial vector meson. The NLO decay amplitude is divided into the vertex correction and the hard spectator…

We study the long-distance contribution to $B_s\to\mu^+\mu^-$ decay, which is generated by the two-photon intermediate state via $B_s\to\gamma^*\gamma^*\to\mu^+\mu^-$ transition. It is found that the dispersive two-photon amplitude can…

A systematic approach to long-distance effects in exclusive radiative weak $B$ decays is presented, based on a combination of the heavy quark limit with perturbative QCD. The dominant long-distance effects, connected with weak annihilation…

We estimate the long distance (LD) contribution to the magnetic part of the $s \to d\gamma$ transition using the Vector Meson Dominance approximation $(V=\rho,\omega,\psi_i)$. We find that this contribution may be significantly larger than…

We investigate a new method to probe the helicity of the photon emitted in the b -> s gamma transition. The method relies on the observation of interference effects between two resonance contributions, B -> K*(K gamma) gamma and B ->…

We present first calculations of new long-distance contributions to $B_s \to \gamma \gamma$ decay due to intermediate $D_s$ and $D_s^*$ meson states. The relevant $\gamma$ vertices are estimated using charge couplings and transition moment…

We discuss the $\mbox{M1}$ radiative transitions $D^*\rightarrow D\gamma$, $D_{s}^*\rightarrow D_s\gamma$, $B^*\rightarrow B\gamma$, and $B^*_{s}\rightarrow B_s\gamma$. A relativistic potential model is proposed. The corresponding…

Motivated by the observation of the decay B to K* gamma by the CLEO collaboration, we have systematically analyzed the weak radiative decay Lambda_b to Lambda gamma, evaluating the confined effects of quarks in the covariant oscillator…

We analyze the short and long distance contributions to inclusive $B \rightarrow X_d \gamma$ decay, paying particular attention to the dependence on the Cabibbo-Kobayashi-Maskawa parameter $V_{td}$. We discuss penguin diagrams with internal…

We re-analyse the long distance contributions to the process $b \to s l^+ l^-$. Full $q^2$-behavior of the vector meson dominance amplitude is used together with the effect of Terasaki suppression, and comparisons with the previous results…

We survey the possibilities of detecting the $s \rightarrow d \gamma$ transition in kaon and hyperon radiative decays. In the more frequent decays, like $K^+ \rightarrow \pi^+ \pi^o \gamma$, $K^+ \rightarrow \pi^+ \ell^+ \ell^-$, the…