Related papers: Results for Precision Observables in the Electrowe…
Results are presented for the momentum dependent two-loop contributions of O(alpha_t alpha_s) to the masses and mixing effects in the Higgs sector of the MSSM. They are obtained in the Feynman-diagrammatic approach using a mixed…
We present the first calculation of the two-loop electroweak fermionic correction to the flavour-dependent effective weak-mixing angle for bottom quarks, sin^2 theta_{eff}^{b anti-b}. For the evaluation of the missing two-loop vertex…
In this thesis, higher-order corrections to the perturbative expansions of scattering amplitudes involving the Higgs boson in the framework of Quantum Chromodynamics are evaluated, where we focus on processes that are mediated through…
We consider for the first time the leading large top mass corrections, arising at higher order in electroweak interactions, to the rare decays $K\to\pi\nu\bar\nu$ and the related modes $B\to X_s\nu\bar\nu$ and $B\to l^+l^-$. Higher order…
We present the calculation of the so far missing ${\cal O}(\alpha^2\alpha_\mathrm{s})$ corrections to the quantity $\Delta r$, which relates the Fermi constant to the W-boson mass, and enables precision predictions of the latter. While the…
We present the currently most precise predictions for the $W$-boson mass and the leptonic effective mixing angle $\sin^2\theta_{\text{eff}}$ in the aligned Two-Higgs-Doublet Model. The evaluation includes the full one-loop result, all known…
The corrections induced by a heavy top on the main precision observables are now available up to O(alpha^2 mt^2/mw^2). The new results imply a significant reduction of the theoretical uncertainty and can have a sizable impact on the…
We analyse the impact of LHC and Tevatron Higgs data on the viability of the Standard Model with a sequential fourth generation (SM4), assuming Dirac neutrinos and a Higgs mass of 125 GeV. To this end we perform a combined fit to the signal…
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…
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.…
The search for new physics signals in Higgs precision measurements plays a pivotal role in the High-Luminosity Large Hadron Collider (HL-LHC) and future colliders programs. The Higgs properties are expected to be measured with great…
We elaborate on a recently suggested effective Lagrangian for charged-current and neutral-current electroweak interactions which in comparison with the standard electroweak theory contains three free parameters $\Delta x, \Delta y$,…
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…
The precise determination of the Higgs self-couplings is an essential task for understanding electroweak symmetry breaking and probing physics beyond the Standard Model (SM). The calculation of two-loop corrections to scalar couplings is…
We calculate the two-loop QCD correction to the scalar quark contributions to the electroweak gauge-boson self-energies at zero momentum-transfer in the supersymmetric extension of the Standard Model. We then derive the $O(\alpha_s)$…
We perform a comprehensive study of the Higgs couplings, gauge-boson couplings to fermions and triple gauge boson vertices. We work in the framework of effective theories including the effects of the dimension-six operators contributing to…
In this proceeding, we highlight the computation of leading fermionic three-loop corrections to electroweak precision observables (EWPOs) accomplished recently. We summarize the numerical analysis and provide an outlook.
Recent developments in the public code $\texttt{FeynHiggs}$ for the prediction of the Standard Model-like Higgs mass in the Minimal Supersymmetric Standard Model are presented. Improvements in the prediction based on an effective-field…
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…
We calculate the three-loop master integrals of Ref. [1] [arXiv:1709.02160] in analytic form. This allows us to present the fermionic contributions to the $\Delta B=2$ Wilson coefficients of the $B$-$\bar B$ decay matrix in…