Related papers: Two-loop virtual corrections to B --> X_s l^+ l^- …
We calculate the radiative corrections to the decays $\tau\to M \nu_\tau$ and $\pi \to l \nu_\l$, where the meson $M$ is $M=\pi$ or $K$ and the lepton $l$ is $l = e$ or $\mu$. We perform a complete calculation, which includes internal…
We consider the error budget for the calculation of the LEP/SLC luminosity in the Monte Carlo event generator BHLUMI4.04 from the standpoint of new calculations of the exact result for the O(alpha) correction to the process e+ e- -> e+ e- +…
The decay of the Standard Model Higgs boson into four leptons via a virtual W-boson or Z-boson pair is one of the most important decay modes in the Higgs-boson search at the LHC. We present the complete electroweak radiative corrections of…
In the determination of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$ from inclusive semileptonic $B$-meson decays, moments of the leptonic invariant mass spectrum constitute valuable observables. To evaluate them with sufficient…
The deviation of the measurement of $R_{D}$ ($R_{D^{*}}$) from the Standard Model (SM) expectation is $2.3\sigma$ ($3.1\sigma$). $R_{D}$ ($R_{D^{*}}$) is the ratio of the branching fraction of $\overline{B} \rightarrow…
We compute O(alpha_s^2) QCD corrections to the lepton invariant mass spectrum in the decay b --> u l nu_l, relevant for the determination of the CKM matrix element |V_{ub}|. Our method can also be used to evaluate moments of the lepton…
A model-independent analysis for the exclusive, rare B -> K^* l^+ l^- decay is presented. Systematically studied are the experimentally measured quantities, such as, branching ratio, forward-backward asymmetry, longitudinal polarization of…
Two-loop contributions to the electromagnetic form factors are calculated in the kinematic regime close to the fermion-antifermion threshold. The results are presented in an expansion in the velocity $\beta$ of the fermions in the c.m.…
We study two--loop renormalization in $(2+\epsilon)$--dimensional quantum gravity. As a first step towards the full calculation, we concentrate on the divergences which are proportional to the number of matter fields. We calculate the…
In the framework of the Standard Model we present predictions for partial widths, double and single differential distributions, and forward--backward lepton asymmetries for four-leptonic decays $B^- \to \mu^+\mu^- {\bar \nu}_e\, e^-$, $B^-…
In this paper, we present the calculations for $H\rightarrow f\bar{f}\gamma$ in the $U(1)_{B-L}$ extension for Standard Model. Analytic results for one-loop form factors in the decay process are expressed in terms of the scalar one-loop…
We put forward the framework of simplified leptoquark models: simple extensions of the Standard Model that serve as benchmarks to test the interactions of leptons with new colored degrees of freedom considered, for instance, in leptoquark…
A sensitive search for the rare decays \Omega^- \to \Lambda \pi^- and \Xi^0 \to p \pi^- has been performed using data from the 1997 run of the HyperCP (Fermilab E871) experiment. Limits on other such processes do not exclude the possibility…
The O(alpha) electroweak radiative corrections to gamma gamma --> WW --> 4f within the electroweak Standard Model are calculated in double-pole approximation (DPA). Virtual corrections are treated in DPA, leading to a classification into…
We estimate \Delta Gamma_d/\Gamma_d, including 1/m_b contributions and part of the next-to-leading order QCD corrections, and find it to be around 0.3%. We show the methods to measure \Delta Gamma_d/\Gamma_d by using at least two different…
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…
General expressions for the double-lepton polarizations in the (B -> K l^+ l^-) decay are obtained, using model independent effective Hamiltonian, including all possible interactions. Correlations between the averaged double-lepton…
We reinvestigate the leading QCD corrections to the radiative decay $b \to s \gamma for supersymmetric extensions of the Standard Model. Although the major contributions to the corrections originate from the running of the effective…
The O(alpha) electroweak radiative corrections to gamma gamma --> WW --> 4f within the electroweak Standard Model are calculated in double-pole approximation (DPA). Virtual corrections are treated in DPA, and real-photonic corrections are…
A theoretical analysis of the partial inclusive B-->X_s gamma decay rate with a cut E_gamma>E_0 on photon energy must deal with short-distance contributions associated with three different mass scales: the hard scale m_b, an intermediate…