相关论文: Short Distance Analysis of $\bar B -> D^{(*)0} e+e…
The semileptonic weak decay process of the $\Lambda_c$ baryon to the neutron $\Lambda_c\rightarrow ne^+\nu_e$ is examined. The transition form factors are investigated with light-cone QCD sum rules. The differential decay width is obtained…
In this work we use the heavy-quark-light-diquark picture to study the semileptonic decay $\Lambda_b \to \Lambda_c+l+\bar{\nu}_l$ in the so-called hybrid scheme. Namely, we apply the heavy quark effective theory (HQET) for larger $q^2$…
We present a compressive study on rare semileptonic $B_c \to D^{(*)}\tau \bar \nu_\tau$ decays involving $b \to u \tau \bar \nu_\tau$ quark level transitions in an effective field theory approach. We consider the presence of an additional…
The recent experimental developments require a more precise theoretical study of weak decays of heavy baryon $\Lambda_b^0$. In this work, we provide an updated and systematic analysis of both the semi-leptonic and nonleptonic decays of…
The b -> ssdbar and b -> ddsbar decays are highly suppressed in the SM, and are thus good probes of new physics (NP) effects. We discuss in detail the structure of the relevant SM effective Hamiltonian pointing out the presence of nonlocal…
We report a study of the decays B0 -> J/psi K(*)0 pi+ pi-, which involve the creation of a u u-bar or d d-bar quark pair in addition to a b-bar -> c-bar(c s-bar) decay. The data sample consists of 110 1/pb of p p-bar collisions at sqrt{s} =…
We study the exclusive semileptonic rare $B_c^+ \to D^+ \nu \bar{\nu}$ decay in the framework of light-cone quark model. The transition form factors $f_{+}(q^2)$ and $f_{T}(q^2)$ are evaluated in the time-like region using the analytic…
We review in brief the threshold expansion, a method to perform the expansion of Feynman integrals near the heavy quark-antiquark threshold, and its relation to the construction of two effective theories, non-relativistic QCD (NRQCD) and…
By analyzing a data sample of $e^+e^-$ collisions with center-of-mass energy $\sqrt{s}=3.773$~GeV, corresponding to an integrated luminosity of $7.9~\rm {fb}^{-1}$ collected with the BESIII detector operating at the BEPCII collider, we…
Angular and energy distributions for leptons and bottom quarks in the process e+e- --> t tbar --> l/b ... have been calculated assuming the most general top-quark couplings. The double distributions depend both on modification of the…
We examine the spectra and radiative decays of the cc-bar and bb-bar systems using a model which incorporates the complete one-loop spin-dependent perturbative QCD short distance potential, a linear confining term including (spin-dependent)…
Motivated by the potential prospects of the $B_{c}^{\ast}$ meson samples at hadron colliders, the bottom-changing $B_{c}^{\ast}$ ${\to}$ ${\psi}(1S,2S)P$, ${\eta}_{c}(1S,2S)P$ weak decays are first studied with the perturbative QCD…
Next-to-Leading-Order(NLO) QCD corrections to double J/psi production in e^+e^- annihilation at sqrt{s}=10.6 GeV are calculated. We find that they greatly decrease the cross section, with a K factor (NLO/LO) ranging from -0.31 to 0.25…
We report a study of the decay $B^0\rightarrow D K^+\pi^-$ followed by $D\rightarrow K^-\pi^+$, where $D$ indicates $D^0$ or $\bar{D}^0$. We reconstruct the $D K^+\pi^-$ state in a phase space corresponding to $D K^{*}(892)^0$. The…
We have analyzed the latest NA50 data on $J/\psi$ suppression in Pb + Pb collisions. $J/\psi$ production is assumed to be a two step process, (i) formation of $c\bar{c}$ pair, which is accurately calculable in QCD and (ii) formation of…
We present an approach which allows for modifications of the (minimal) analytic QCD model of Shirkov, Solovtsov et al. The discontinuity function of the (minimal) analytic QCD coupling parameter is changed at the low time-like momenta by a…
Theoretical predictions for B decay rates are rewritten in terms of the Upsilon(1S) meson mass instead of the b quark mass, using a modified perturbation expansion. The theoretical consistency of this expansion is shown both at low and high…
The nonleptonic decay $\Xi^0_c \to \Lambda^+_c \pi^-$ with $\Delta C=0$ is systematically studied in the framework of the covariant confined quark model with accounting for both short and long distance effects. The short distance effects…
The recent observation of the decay $\ob \to \Lambda_c^+ \bar p$ suggests that related decays may soon be visible at $e^+ e^-$ colliders. It is shown how these decays can shed light on strong final-state phases and amplitudes involving the…
We investigate the ${\cal O}(\alpha_s)$ correction to $e^+e^-\to J/\psi+\eta_{c2}$ in the NRQCD factorization approach. A detailed comparative study between $e^+e^-\to J/\psi+\eta_{c2}$ and $e^+e^-\to J/\psi+\chi^\prime_{c1}$ at $B$ factory…