相关论文: QCD Corrections in Gamma_sl(B)
We study the Lambda_QCD/M_B corrections from subleading shape functions in inclusive B-meson decays. We propose a natural and smooth interpolation from the endpoint region to the full phase space, and derive expressions for the triple…
Semileptonic $B$($B_s, B_c$) decays are investigated systematically in the light-cone QCD sum rules. Special emphasis is put on the LCSR calculation on weak form factors with an adequate chiral current correlator, which turns out to be…
A brief review of the problem of the determination of light-quark masses from QCD sum rules for the correlators of scalar and pseudoscalar currents is given. Special attention is paid to the description of the large-$N_f$ results, obtained…
We discuss the QCD corrections to the large-$m_t$ electroweak contributions to $\Delta r$ and to the process $Z\to b \bar b$ as two of the most representative examples. This needs the construction of an effetive field theory below the top…
We extend previous computations of the second order QCD corrections to semileptonic b \to c inclusive transitions, to the case where the charged lepton in the final state is massive. This allows accurate description of b \to c \tau \bar…
The analytic relation between the \bar {MS} and the pole quark masses is computed to O(\alpha_s^3) in QCD. Using this exact result, the accuracy of the large \beta_0 approximation is critically examined and the implications of the obtained…
An all-order resummation is performed for the effect of the running of the strong coupling in the zero recoil sum rule for the axial current and for the kinetic operator \vec\pi^2. The perturbative corrections to well-defined objects of OPE…
Two-gluon radiative corrections to the $b\to c\ell\nu$ decay width have been computed analytically as an expansion in terms of \frac{m_c}{m_b} << 1 in the kinematical limit of zero lepton invariant mass. The obtained results match smoothly…
We present our results for three-loop anomalous dimensions necessary in analyzing $B{\to}X_s\gamma$ decay at the next-to-leading order in QCD. We combine them with other recently calculated contributions, obtaining a practically complete…
The results of analytical evaluation of $O(\alpha_s^2)$ QCD contributions due to the nonvanishing quark masses to $\Gamma_{H\rightarrow q_f\overline{q}_f}$ are presented. The ``triangle anomaly'' type contributions are included. As a…
The rate of the semileptonic decay b to c l v is calculated with order alphas^2 accuracy, as an expansion around the limit of equal masses of the b and c quarks. Recent results obtained around the limit of the c-quark much lighter than b…
We discuss the resummation of the potentially large O((\beta_0\alpha_s)^n) QCD corrections to the total cross section of the process e^+e^- \to t \bar t near the threshold. In this approximation, the cross section factorization into the…
We show that the O(Lambda) ambiguity in the pole mass can be fixed in a natural way by introducing a modified nonperturbative V-scheme momentum space coupling tilde-alphaV(q) where the confining contributions have been subtracted out. The…
We use the Operator Product Expansion (OPE) of quark vacuum polarization functions to show that the dispersion relation of Kniehl and Sirlin will yield the correct result to all orders in $\alpha_s$ when applied to the QCD correction to the…
We consider in detail various theoretical uncertainties of the perturbative predictions for the decay width of $H^0\rightarrow b\overline{b}$ process in the region $50\ GeV< M_H\leq 2M_W$. We calculate the order…
Within the framework of nonrelativistic QCD (NRQCD) factorization, we compute the three-loop QCD corrections to the decay constant of $B_c$. We reconstruct the analytical expressions for the three-loop renormalization constant and the…
The use of conformal expansions for predictions in quantum chromodynamics is discussed as a way to avoid renormalization scheme and scale ambiguities, as well as factorial growth of perturbative coefficients due to renormalons. Special…
This report summarises recent advances made in the calculation of the NNLO QCD corrections to the width difference $\Delta\Gamma_s$ in the $B_s-\overline{B}_s$ system. The inclusion of the effects due to current-current operators leads to…
This talk covers recent theoretical progress in exclusive semileptonic rare B-decays at low hadronic recoil. The efficient parametric suppression of the 1/mb corrections in this region provides opportunities to probe the Standard Model and…
In this paper we calculate first order radiative QCD corrections to the decay process $b\to cW^-(\to\ell^-\bar\nu_\ell)$ of a polarized bottom quark. Taking into account both the bottom and charm quark masses, the analytical expressions…