相关论文: Short Distance Analysis of $\bar B -> D^{(*)0} e+e…

The decays $B^+\to D_{s,d}^+e^+e^-$ and $B^+\to D_{s,d}^{*+}e^+e^-$ proceed through a weak and an electromagnetic interaction. This is a typical ``long distance'' process, usually difficult to compute systematically. We propose that over a…

QCD corrections to the electron positron annihilation cross-section into hadrons and to the hadronic $Z$ boson decay rate are reviewed. Formal developments are introduced in a form particularly suited for practical applications. These…

It was argued long ago that eta_b could be observed through the eta_b => Jpsi(=> mu+ mu-) Jpsi(=> mu+ mu-) decay chain. Recent calculations indicate that the width of eta_b into two Jpsi is almost 3 orders of magnitude smaller than the one…

Motivated by the recent measurement of the upper limit of ${B}^0 \to J/\psi D$ branching ratio, which is important in accounting for the soft $J/\psi$ production in B decays, we investigate ${B}^0 \to J/\psi D^{(\star)}$ and $\eta_c…

Besides the conventional strong and electromagnetic decay modes, the $J/{\psi}$ particle can also decay via the weak interaction in the standard model. In this paper, nonleptonic $J/{\psi}$ ${\to}$ $D_{s,d}{\pi}$, $D_{s,d}K$ weak decays,…

We report a first, complete lattice QCD calculation of the long-distance contribution to the $K^+\to\pi^+\nu\bar{\nu}$ decay within the standard model. This is a second-order weak process involving two four-Fermi operators that is highly…

We present a model-independent description of the exclusive rare decays B-> K* e+e- in the low recoil region (large lepton invariant mass q^2 ~ m_b^2). In this region the long-distance effects from quark loops can be computed with the help…

It has been argued long ago that eta(b) could be observed through the eta(b) => J/psi(=> mu+ mu-) J/psi(=> mu+ mu-) decay chain. Recent calculations indicate that the width of eta(b) into two J/psi is almost three order of magnitude smaller…

We have performed an analysis of the $e^+ e^- \to D^{(*)} \bar D^{(*)}$ data in the region of the $\psi(4040)$ and $\psi(4160)$ resonances which have a substantial overlap and require special care. By using the $^3 P_0$ model to relate the…

In decay modes $B^0 \to D_s^{(*)+} D_s^{(*)-}$ and $B_s^0 \to D^{(*)+} D^{(*)-}$, none of quarks in final states is the same as one of $B$ meson. They can occur only via annihilation diagrams in the Standard Model. In the heavy quark limit,…

We report on our recent attempts to determine the short distance behaviors of general 2-baryon and 3-baryon forces, which are defined from the Nambu-Bethe-Salpeter(NBS) wave function, by using the operator product expansion and a…

We calculate the leading power corrections to the decay rates, distributions and hadronic spectral moments in rare inclusive \bxsll decays in the standard model, using heavy quark expansion (HQE) in $(1/m_b)$ and a phenomenological model…

Intrigued by a recent Belle result for a large direct CP asymmetry in $B^0\to D^+D^-$, we study the effects of a $\bar b\to \bar uu\bar d$ quark transition by combining the asymmetry information with rates and asymmetries in isospin-related…

The decay process $B\to D^+ D^- \pi^0$ is an interesting channel for the investigation of CP violating effects in the $b-$ sector. We write down a decay amplitude constrained by a low-energy theorem, which also includes the contribution of…

In this work we use the low-energy EFT called potential non-relativistic QCD (pNRQCD) to calculate the partial decay width of different $b\bar{b}$-states undergoing an electric dipole transition at next-to-next-to leading order (NNLO).…

Motivated by the first LHCb searches for the rare $\bar{B}_{s,d}^{0} \to J/\psi\mu^{+}\mu^{-}$ decays, we perform a detailed study of these processes within the QCD factorization formalism. Since the transverse size of the $J/\psi$ meson is…

The decays of exotic states discovered experimentally always proceed via the strong and electromagnetic interactions. Recently, a tetraquark state with the quark content $bc\bar{q}\bar{q}$ was predicted by Lattice QCD simulations. It is…

In this paper, we evaluate, up to QCD next-to-next-to-next-to-leading order, the $B_c^*$ decay constant, which, within the nonrelativistic QCD (NRQCD) framework, is factorized as the product of the short-distance coefficient (SDC) and the…

We calculate the relativistic correction to $J/\psi$ production in the color-singlet process $e^{+}e^{-}\to J/\psi+gg$ at B-factories. We employ the non-relativistic QCD (NRQCD) factorization approach, where the short-distance coefficients…

The decays $B_c^+ \to B_{a} \bar \ell \nu_\ell$ and $B_c^+ \to B_{a}^{*}(\to B_a \gamma) \bar \ell \nu_\ell$, with $a=s,d$ and $\ell=e,\mu$, are studied in the Standard Model (SM) and in the extension based on the low-energy Hamiltonian…