Related papers: Large 2HDM(II) one-loop corrections in leptonic ta…
The two-loop corrections to the electroweak gauge bosons quartic couplings growing quadratically with the Higgs boson mass are calculated in the Standard Model in the limit of large Higgs mass. The corrections to WWWW, WWZZ and ZZZZ…
This note is devoted to the calculation of the two-loop $O(G_F {M_H}^2)$ radiative corrections to the Higgs decay width $H \to \gamma \gamma $ for large values of the Higgs boson mass $M_H$ within the Minimal Standard Model. The use of the…
One-loop contributions for decay process $H^{\pm} \rightarrow W^{\pm}Z$ within the Two-Higgs-Doublet Model are computed in the general $\mathcal{R}_{\xi}$ gauge, and its phenomenological applications at future muon--TeV colliders are…
We discuss the Type-X (lepton-specific) two Higgs doublet model as a solution of the anomaly of the muon $g-2$. We consider various experimental constraints on the parameter space such as direct searches for extra Higgs bosons at the LEP II…
We study the effect of a light charged Higgs appearing in supersymmetric models containing two Higgs doublets on the measurement of leptonic branching ratios of the W boson at LEP. We show that the $2.8 \sigma$ excess of the branching ratio…
The lepton-number-violating decays of singly-charged Higgs bosons H^\pm are investigated in the minimal type-(I+II) seesaw model with one SU(2)_L Higgs triplet \Delta and one heavy Majorana neutrino N_1 at the TeV scale. We find that the…
Results for the two-loop corrections to the Higgs-boson masses of the MSSM with complex parameters of $\mathcal{O}{\left(\alpha_t^2+\alpha_t\alpha_b+\alpha_b^2\right)}$ from the Yukawa sector in the gauge-less limit are presented. The…
We compute the two-loop corrections to the coefficient of the b --> s gamma magnetic penguin present in the limits of heavy top and/or heavy higgs. This kind of corrections affects in a significant way the observables measured at LEP. On…
The charged-Higgs boson contributions to the Wilson coefficients C_7 and C_8, relevant for the decay B -> X_s gamma, are discussed in supersymmetric models at large tan beta. These contributions receive two-loop O(alpha_s tan beta)…
The four self-couplings $\lambda_{hhh}$, $\lambda_{hhH}$, $\lambda_{hHH}$, $\lambda_{HHH}$ and decay width $\Gamma(H \to hh)$ are calculated taken into account one-loop $t,b,c$ - (s)quarks, $\tau$ - (s)lepton corrections in the framework of…
We calculate the dominant ${\rm O}\left(G_F^2M_H^4\right)$ two-loop electroweak corrections to the fermi\-onic decay widths of a heavy Higgs boson in the Standard Model. Use of the Goldstone-boson equivalence theorem reduces the problem to…
We compute the dominant two-loop corrections to the Higgs trilinear coupling $\lambda_{hhh}$ and to the Higgs quartic coupling $\lambda_{hhhh}$ in models with extended Higgs sectors, using the effective-potential approximation. We provide…
We calculate the leading logarithmic QCD corrections to the decay B_s --> \gamma \gamma in the two Higgs doublet model (2HDM) including O_7 type long distance effects and estimate the restrictions of the 2HDM parameters, tan\beta and m_H,…
Only small regions in the $m_{t} - \tan\beta$ plane are allowed when considering simultaneously (assuming the MSSM) coupling constant unification and (minimal) GUT relations among Yukawa couplings (i.e., $h_{b} = h_{\tau}$ at the…
We study the effects induced by excited leptons on the leptonic tau decay at one loop level. Using a general effective lagrangian approach to describe the couplings of the excited leptons, we compute their contributions to the leptonic…
The non-decoupling effects of heavy Higgs bosons on the process $e^+e^- \to W^+_LW^-_L$ are discussed in the two Higgs-doublet model. The one-loop corrections to the cross section are calculated by using the equivalence theorem and the…
A systematic study of one-loop contributions to the decay channels $h\rightarrow l\bar{l}\gamma$ with $l=\nu_{e,\mu, \tau}, e, \mu$, performed in Higgs extended versions of the Standard Model, is presented in the 't Hooft-Veltman gauge.…
We consider a two-loop contribution of Higgs-mediated penguin diagram to $B(B_s \to \mu^+\mu^-)$ at large $\tan\beta$ in the MSSM, motivated by a recently proposed two-loop magnetic penguin diagrams by Chen and Geng [1]. Typically the…
We compute the contributions to rare top decays $t\rightarrow cZ$ and $t\rightarrow ch_1$ from the scalar sector in the 2HDM type III with CP violation, where $h_1$ is the Standard Model Higgs boson. The branching ratio for $BR(t\rightarrow…
The charged-Higgs contributions to the decay \bar{B} -> X_s gamma are discussed in the minimal supersymmetric standard model at large tan beta. These contributions receive two-loop O(alpha_s tan beta) corrections by squark-gluino subloops,…