Related papers: Leading Electroweak Two-Loop Corrections to Precis…
The parameter $\epsilon_K$ measures $CP$ violation in the neutral kaon system. It is a sensitive probe of new physics and plays a prominent role in the global fit of the Cabibbo-Kobabyashi-Maskawa matrix. The perturbative theory uncertainty…
The effective renormalizable theory describing electromagnetic and strong interactions of quarks of five light flavors ($n_f = 5$ QCD$\times$QED) is considered as a low-energy limit of the full Standard Model. Two-loop relation between the…
We discuss a recent analysis of a dominant two-loop electroweak correction, of O(G_F M_t^2), to the partial width of the decay of an intermediate-mass Higgs boson into a pair of photons. The asymptotic-expansion technique was used in order…
The current status of electroweak precision observables in the Minimal Supersymmetric Standard Model (MSSM) is reviewed. We focus in particular on the $W$ boson mass, M_W, the effective leptonic weak mixing angle, sin^2 theta_eff, the…
In the minimal supersymmetric model (MSSM), the upper limit of the lightest Higgs boson mass, $\mhl$, depends strongly on the top quark mass, $m_t$. We have computed the dominant two-loop radiative corrections to this upper limit of $\mhl$…
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…
Recent electroweak two-loop corrections in the Minimal Supersymmetric Standard Model (MSSM) are reviewed. They have been obtained with the help of the programs FeynArts and TwoCalc, making use of the recently completed MSSM model file for…
The assumption that two-loop top corrections are well approximated by the $O(G_mu^2 mt^4)$ contribution is investigated. It is shown that in the case of the ratio neutral-to-charged current amplitudes at zero momentum transfer the $O(G_mu^2…
In the supersymmetric extension of the Standard Model we derive the two-loop QCD corrections to the scalar quark contributions to the electroweak precision observables entering via the rho parameter. A very compact expression is derived for…
Recent results of two-loop contributions to the muon (g-2) in the Standard Model and its supersymmetric extension are presented. In the SM the EW contributions are fixed according to the Higgs boson mass measured at LHC. In the MSSM we…
We present the results of a first global fit to the electroweak observables in the MSSM. The best fit selects either very low or very large values of ~$\tan\beta$ ~and, correspondingly, chargino (higgsino--like) and stop or the ~$CP-$odd…
We analytically calculate the dominant two-loop electroweak correction, of O(G_F^2 m_t^4), to the partial width of the decay of a Higgs boson, with mass M_H << m_t, into a bottom-quark pair, and describe the most important conceptual and…
We discuss the impact of the two-loop corrections to the Higgs mass in the NMSSM beyond $O(\alpha_S(\alpha_b + \alpha_t))$. For this purpose we use the combination of the public tools SARAH and SPheno to include all contributions stemming…
New heavy particles in an SU(2)_L multiplet, sometimes introduced in extensions of the standard model, have highly degenerate tree-level mass M if their couplings to the Higgs bosons are very small or forbidden. However, loop corrections…
We present the full ${{\cal O}}(\alpha)$ electroweak radiative corrections to associated Higgs top pair production in $e^+e^-$ collisions. We combine these results with a new calculation of the full one-loop QCD corrections. The computation…
Two-loop electroweak corrections to polarized Moller scattering are studied in two different schemes at low energies. We find the finite $Q^2$ corrections to be well under control. The hadronic and perturbative QCD corrections to the…
Future electron-position colliders, such as CEPC and FCC-ee, have the capability to dramatically improve the experimental precision for W and Z-boson masses and couplings. This would enable indirect probes of physics beyond the Standard…
We calculate the Yukawa corrections of order ${\cal O}(\alpha_{ew}m_{t(b)}^2/m_W^2)$, ${\cal O}(\alpha_{ew}m_{t(b)}^3/m_W^3)$ and ${\cal O}(\alpha_{ew}m_{t(b)}^4/m_W^4)$ to the widths of the decays $\tilde t_2\to \tilde t_1 + (h^0,H^0,A^0)$…
Full O(alpha) electroweak corrections for gamma-gamma-> W+W- are calculated including virtual corrections, soft and hard real photon and Z-boson emission. The corrections are quite large ranging from -2.5% at 500 GeV to -18% at 2 TeV,…
We calculate the two--loop electroweak corrections to the fermionic decay width of the Higgs boson at leading order in $m_{H}$. The sum of one--loop and two--loop radiative corrections turns out to be at 6% level over the whole range of…