Related papers: Binding two-loop vacuum-polarization corrections t…
We briefly report our calculation of the 2-loop coefficient of the coupling constant renormalization function Z_g in lattice perturbation theory. The quantity under study is defined through g_0 = Z_g g, where g_0 (g) is the bare…
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 an analytical calculation of the leading three-loop radiative correction to the S-parameter in the Standard Model in the large Higgs mass limit. Numerically, S^(3) = 1.1105*g^4/(1024 pi^3)*m_H^4/M_W^4. When combined with the…
Using an effective potential approach, we compute two-loop radiative corrections to the MSSM lightest ${\cal CP}$-even Higgs boson mass $M_{h^0}$ to ${\cal O}(\alpha_t^2)$ for arbitrary left-right top-squark mixing and $\tan\beta$. We find…
We have completed the calculation of pure-recoil corrections of order $(Z \alpha)^6$ to Coulombic bound states of two spin-1/2 fermions without approximation in the particle masses. Our result applies to systems of arbitrary mass ratio such…
In order to reach a precision of $0.2\%$ on the hadronic vacuum polarization (HVP) contribution to the anomalous magnetic moment of the muon, $(g-2)_\mu$, such that the full Standard-Model prediction matches in precision the direct…
The leading-order two-loop vacuum-polarization potential, linear in the Coulomb field of a nucleus, was first derived in the seminal 1955 work of K\"all\'en-Sabry. The higher-order two-loop vacuum-polarization corrections, however, have…
In order to investigate the systematics of the loop expansion in high temperature gauge theories beyond the leading order hard thermal loop (HTL) approximation, we calculate the two-loop electron proper self-energy in high temperature QED.…
We present a new calculation of the order alpha^2 (Z alpha)^5 correction to the Lamb shift, which uses methods developed for multi-loop calculations.
We present the two-loop virtual corrections to Standard Model Higgs boson pair production via gluon fusion $gg\to HH$ in the heavy top quark limit. Based on this result, we evaluate the corresponding cross section at the LHC at 14 TeV in…
We consider electroweak (EW) virtual corrections to $2\to 2$ fermion scattering processes mediated by a vector boson $V$ ($V=W^\pm,Z$) in the pole approximation. As is well known, the computation can be organised into factorisable and…
We investigate the possible size of two-loop radiative corrections to the Higgs trilinear coupling $\lambda_{hhh}$ in two types of models with extended Higgs sectors, namely in a Two-Higgs-Doublet Model (2HDM) and in the Inert Doublet Model…
We compute three-loop corrections to the process $gg\to HH$ originating from one-particle reducible diagrams. This requires the computation of two-loop corrections to the gluon-gluon-Higgs vertex with an off-shell gluon. We describe in…
In the last two years the renormalization group functions for the couplings and fields of the Standard Model have been computed at three-loop level. The evolution of the self-coupling $\lambda$ of the Standard Model Higgs boson is of…
We compute the complete two-loop electroweak corrections to the Higgsstralung process $e^+e^-\rightarrow HZ$ at the future Higgs factory. The Feynman integrals involved in the computation are decomposed into linear combinations of a minimal…
Results of evaluating the leading order $\alpha_s$ corrections to the correlator of tensor currents in pure gluodynamics are presented. These corrections to the parton result for the correlator are not large numerically that allows one to…
We compute next-to-leading order virtual two-loop corrections to the process $gg\to ZZ$ in the low- and high-energy limits, considering the contributions with virtual top quarks. Analytic results for all 20 form factors are presented…
We accomplish for the first time the two-loop computation of the leading-twist contribution to the pion electromagnetic form factor by employing the effective field theory formalism rigorously. The next-to-next-to-leading-order…
We present the systematic QED treatment of the electron correlation effects on the $g$ factor of lithiumlike ions for the wide range of nuclear charge number $Z= 14$ -- $82$. The one- and two-photon exchange corrections are evaluated…
We compute the one loop vacuum polarization from massless, minimally coupled scalar QED in a locally de Sitter background. Gauge invariance is maintained through the use of dimensional regularization, whereas conformal invariance is…