Related papers: Convolution formula and finite W boson width effec…
A supersymmetric model with four generations is proposed, in which the top quark is approximately degenerate in mass with the $W^{\pm}$ gauge boson, $m_t\simeq m_W$, leading to values of $R_b$ in better agreement with the present…
At proposed high energy linear e+e- colliders a large number of W bosons and top quarks will be produced. We evaluate the potential precision to which the decay branching ratios into the various quark species can be measured, implying also…
Higgs boson radiative decays of the form $H\rightarrow f\bar{f}\gamma$ are calculated in the Standard Model using the complete one-loop expressions for the decay amplitudes. Contributions to the radiative width from leptons and light quarks…
The possibility of formation for a bound state of a $t$ quark and a lighter one is investigated using potential model predictions and heavy quark effective theory approach. Resulting estimates for the 1S--2S splitting of the energy levels…
We compute the two-loop BSM contributions to the $h\longrightarrow \gamma\gamma$ decay width in the aligned THDM. We adopt the simplifying assumptions of vanishing EW gauge couplings and vanishing mass of the SM-like Higgs boson, which…
The mass spectra and electromagnetic decay rates of charmonium, bottomonium and B_c mesons are comprehensively investigated in the relativistic quark model. The presence of only heavy quarks allows the expansion in powers of their…
Top quark decays are of particular interest as a mean to test the standard model (SM) predictions, both for dominant (t -> b + W) and rare decays (t -> q + W, cV, cVV, c phi^{0}, bWZ). As the latter are highly suppressed, they become an…
A quantum mechanical wave of a finite size moves like a classical particle and shows a unique decay probability. Because the wave function evolves according to the Schr\"{o}dinger equation, it preserves the total energy but not the kinetic…
We have performed a one-loop calculation of the width of the rare decay H -> Z Z \gamma in the standard model for Higgs boson masses 190 GeV \leq m_H \leq 250 GeV. We find that the most dominant helicity combinations for the Z bosons and…
We compute the two-loop electroweak corrections to the radiative decays of the B meson in the SM. Electroweak effects reduce the Wilson coefficient C_7^eff(mw) by 2.6% for a light Higgs boson of about 100 GeV and are less important for a…
We analytically compute quadratic mass corrections of order $\alpha_s^3 m_q^2/s$ to the absorptive part of the (non-diagonal) correlator of two axial vector currents. This allows us to find the correction of order $\alpha_s^3 m_q^2/M^2_W$…
The calculation of the partial width of the rare t-quark decay into Upsilon-meson, W-boson and b-quark (t -> \Upsilon W b) is presented. The branching ratio equals Br(t -> Upsilon W b) = 1.3 * 10^{-5} that make possible searches for this…
Inspired by a new class of walking technicolor models recently proposed using higher-dimensional technifermions, we consider the oblique corrections from heavy non-degenerate fermions with two classes of higher-dimensional representations…
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…
We analyze the unconventional top quark decay mode t -> H^+ b at the quantum level within the context of general Two-Higgs-Doublet models by including the full electroweak effects from the Yukawa couplings. The results are presented in the…
We present numerical calculations of the partial width of the charged Higgs boson decay into a top quark, $H^- \rightarrow \bar{t} + b + X$, and the partial width of the top quark decay into a light charged Higgs boson $t \rightarrow H^+ +…
We present the first model-independent measurement of the helicity of $W$ bosons produced in top quark decays, based on a 1 fb$^{-1}$ sample of candidate $t\bar{t}$ events in the dilepton and lepton plus jets channels collected by the D0…
We calculate the alpha_s virtual corrections to the decay width for b --> s gluon in the standard model. Also the corresponding order alpha_s bremsstrahlung corrections are systematically calculated in this paper. The combined result is…
In the large $N_c$ limit, all hyperon decays involving the same quark diagram $Q\to Q'$ are described by a single weak form factor $\eta_{QQ'}(w)$. No assumption on the mass of $Q$ or $Q'$ is necessary, making our results applicable to both…
A uniform bounded variation estimate for finite volume approximations of the nonlinear scalar conservation law $\partial_t \alpha + \mathrm{div}(\boldsymbol{u}f(\alpha)) = 0$ in two and three spatial dimensions with an initial data of…