相关论文: Factorization theorems for exclusive heavy-quarkon…

Recent progress in the factorization of exclusive decays of heavy quarkonia into long-distance and short-distance contributions is presented. The role of higher Fock states and colour-octet contributions is outlined.

The total cross section for the production of massive quarks in electron positron annihilation can be predicted in perturbative QCD. After expansion in m^2/s the quartic terms, i.e. those proportional to m^4/s^2, are calculated up to order…

We investigate the double logarithmic corrections $\alpha_s\ln^2 x$, x being a parton momentum fraction, in two-body nonleptonic B meson decays in collinear factorization theorem of perturbative QCD (PQCD). It is found that these…

A factorization theorem for $P$-wave quarkonium production, recently derived by Bodwin, Braaten, Yuan and Lepage, is applied to $\Upsilon \to \chi_{cJ} + X$, where $\chi_{cJ}$ labels the ${}^3 P_J$ charmonium states. The widths for…

We study the hadronic charmless two-body B decays to final states involving pseudoscalar and vector mesons with QCD factorization approach, including the contributions from the chirally enhanced power corrections and weak annihilations. The…

We calculate the next-to-leading order (NLO) quantum chromodynamics (QCD) corrections to double charmonium production processes $e^+e^-\to\gamma^*\to\eta_c+h_c(1P)/\psi_{1,2}(1D)$ within the non-relativistic QCD (NRQCD) factorization…

We study the production of $C=+$ charmonium states $X$ in $e^+e^-\to \gamma + X$ at B factories with $X=\eta_c(nS)$ (n=1,2,3), $\chi_{cJ}(mP)$ (m=1,2), and $^1D_2(1D)$. In the S and P wave case, contributions of tree-QED with one-loop QCD…

Using the fact that the c-quark inside a charmonium moves with a small velocity v in the charmonium rest-frame, one can employ an expansion in v to study decays of charmonia and results at the leading order for chi_{c0,2} --> gamma gamma…

We present theoretical analysis of paired $B_c$ mesons production in $e^+e^-$ annihilation at different energy scales taking into account full next-to-leading order QCD corrections. Both possible electroweak channels are considered:…

We present threshold enhanced QCD corrections to the bottom quark energy distribution in Higgs boson decay and to hadroproduction in $l^+l^-$ annihilation beyond leading order in the strong coupling constant. This is achieved using the…

We outline a proof of factorization in exclusive processes, taking into account the presence of soft and collinear modes of arbitrarily low energy, which arise when the external lines of the process are taken on shell. Specifically, we…

We calculate the semileptonic branching ratio and the charm counting of inclusive $B$ meson decays using the perturbative QCD formalism. For the nonleptonic decays, we employ the modified factorization theorem, in which Wilson coefficients…

We calculate the standard model predictions for top quark pair production and decay into six fermions at a linear e+ e- collider. We include the factorizable electroweak O(alpha) corrections in the pole approximation and QED corrections due…

The hadronic decays $B\to J/\psi K(K^*)$ are interesting because experimentally they are the only color-suppressed modes which have been measured, and theoretically they are calculable by QCD factorization even the emitted meson $J\psi$ is…

Recent theoretical investigations of two-body hadronic B decays have provided justification for the use of the factorization ansatz to evaluate the B decay matrix elements. Motivated by this, we present simplified formulae for a wide range…

Since b quark mass is not asymptotically large, chirally enhanced corrections which arise from twist-3 wave functions may be important in B decays. We thus evaluate the hadronic matrix elements with the emitted meson described by leading…

We study the radiative decays B -> V gamma (where V=rho, K^*) in the framework of QCD factorisation, and in particular the hard-spectator contributions to the decay amplitudes. For the phenomenologically significant chromomagnetic operator,…

We study the rates and direct CP violations of two-body baryonic $\bar B_{u,d,s}\to {{\rm\bf B}\overline{\rm\bf B}}'$ and $B^-_c\to{{\rm\bf B}\overline{\rm\bf B}}'$ decays, where the final state baryons include low-lying octet and decuplet…

We consider the computation of D and B fragmentation functions in e+e- annihilation. We compare the results of fitting present data using the next-to-leading-logarithmic resummed approach, versus the O(alpha_s^2) fixed-order calculation,…

If the recently-discovered charmonium state X(3870) is a loosely-bound molecule of the charm mesons D^0 and \bar D^{*0} or \bar D^0 and D^{*0}, it can be produced in e^+ e^- annihilation at the \Upsilon(4S) resonance by the coalescence of…