相关论文: Scale Setting in Top Quark Decays

We present updated and comprehensive Standard Model predictions for the inclusive rare decay $B \to X_s \nu\bar{\nu}$. Using a state-of-the-art determination of the short-distance coefficient, including NLO QCD and electroweak effects, and…

The FAC, PMS, and BLM optimization methods are applied to the QED corrections to the muon lifetime in the Fermi V-A theory. The FAC and PMS scales are close to m_e, while the BLM scale nearly concides with the geometric average \sqrt{m_e…

The polarization of the $W$ boson in $t \to W b$ decay is unambiguously predicted by the Standard Model of weak interactions and is a powerful test of our understanding of the $tbW$ vertex. The subsequent $W \to l \nu$ decay serves as a…

We discuss two dedicated observables in exclusive B -> K* l+ l- decay that can be used to study effects of physics beyond the standard model, namely the forward-backward asymmetry in the lepton spectrum and the isospin-asymmetry between…

We present a complete calculation of the QCD corrections (of the order $\alpha_s$) to the width of the decay $H^+ \to t \bar{b}$ within the Minimal Supersymmetric Standard Model. We find that the QCD corrections are quite important, and…

Recent developments in perturbative QCD, leading to the beta function in five-loop approximation are presented. In a first step the two most important decay modes of the Higgs boson are discussed: decays into a pair of gluons and,…

A summary of recent results obtained for higher-order corrections to precision observables in the Standard Model and the Minimal Supersymmetric Standard Model is given. In the Standard Model electroweak two-loop results valid for arbitrary…

We evaluate the effect of a virtual top quark on the coefficient of $\alpha_{s}^{2}$ in the decay rates $\Gamma(Z \rightarrow {\rm hadrons})$ and $\Gamma(Z \rightarrow b\overline{b} )$. We treat the dependence on the top quark mass exactly…

I present a detailed SUSY QCD calculation of the decay rate of the lightest Higgs boson $H^0_2$\ into two gluons, where all quarks and scalar quarks are taken within the relevant loop diagrams. I include the mixing of all the scalar…

We write down the four-dimensional fully differential decay distribution for the top quark decay $t \to Wb \to \ell \nu b$. We discuss how its eight physical parameters can be measured, either with a global fit or with the use of selected…

We consider contributions of non-standard tbW effective operators to the decay of an unpolarized top quark into a bottom quark and a W gauge boson at next-to-leading order in QCD. We find that the dipole operator O_{LR} contribution to the…

Using special linear combinations of finite energy sum rules which minimize the contribution of the unknown continuum spectral function, we compute the decay constants of the pseudoscalar mesons B and B_s. In the computation, we employ the…

We present a brief overview of the recent theoretical progress to describe the K_{l2} and K_{l3} decays. We discuss the interesting probes of the Standard Model offered by these decays such as the extraction of |V_{us}| and the test of the…

We point out that current estimates of form factors fail to explain the non-leptonic decays $B \to \psi K(K^{\ast})$ and that the combination of data on the semi-leptonic decays $D \to K(K^{\ast})\ell \nu$ and on the non-leptonic decays $B…

We give a summary about the various contributions which have to be calculated in order to obtain the next-to-leading logarithmic result for the branching ratio $BR(B \to X_s \gamma)$. Combining all these ingredients, which were obtained by…

The ${\cal O}(\alpha_s)$ QCD corrections to the three-body decay width of the charged Higgs $\Gamma$($H^+\to W^+b\bar{b}$) are discussed in the MSSM model. Our calculations indicate that the standard QCD corrections to the three-body decay…

The top quark decay process $\tcups$ is studied in the Standard Model and the Minimal Supersymmetric Standard Model with conserved and violated $R-$parity. In dealing with the heavy quarkonium, $\ups$, production, we take both color-singlet…

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 study the decay B --> K l^+ l^- for l = e,mu,tau with a softly recoiling kaon, that is, for high dilepton invariant masses sqrt{q^2} of the order of the b-quark mass. This kinematic region can be treated within an operator product…

Corrections of order $\alpha_s^4$ for the axial singlet contributions for the decay rates of the $Z$-boson into hadrons are evaluated in the limit of the heavy top quark mass. Combined with recently finished ${\cal O}(\alpha_s^4)$…