Related papers: Logarithmic two-loop corrections to the Lamb shift…
Nuclear-size corrections of order $(Z \alpha)^5$ and $(Z \alpha)^6$ to the S-state levels of hydrogenic atoms are considered. These nuclear-elastic contributions are somewhat smaller than the polarizability (nuclear-inelastic) corrections…
Corrections of order $\alpha^3(Z\alpha)^5m$ to the Lamb shift and corrections of order $\alpha^3(Z\alpha)E_F$ to hyperfine splitting generated by the insertions of the three-loop one-particle reducible diagrams with radiative photons in the…
The finite operators are derived for the recoil $m\alpha^6(m/M)$ order relativistic corrections (to spin-averaged energy levels) in hydrogen-like atoms and ions in the two- and three-body formalism beyond the adiabatic approximation.…
We present an alternative calculation for the leading Higgs mass dependent one--loop corrections to the standard model Lagrangian, using a background field technique. Cross--sections computed from our one--loop Lagrangian provide a check of…
We present the impact of two-loop corrections on the mass of the lightest Higgs boson in the Minimal R-symmetric Supersymmetric Standard Model (MRSSM). These shift the Higgs boson mass up by typically 5 GeV or more. The dominant corrections…
Recently, the ATLAS and CMS collaborations jointly announced the first evidence of the rare Higgs boson decay channel $H\to Z\gamma$, with a ratio of $2.2\pm 0.7$ times the leading order standard model (SM) prediction. In order to face this…
We report a calculation of relativistic corrections of order $m\alpha^7$ to the Bethe logarithm for the $2^3S$ and $2^3P$ states of helium-like ions. The calculation is required for improving the accuracy of theoretical energies of…
In this article we give a calculation of the two-loop $\sigma$-model corrections to the T-duality map in string theory. We use the effective action approach, and analyze two-loop corrections in a specific subtraction scheme. Focusing on…
We present the complete analytical result for the two-loop logarithmically enhanced contributions to the high energy asymptotic behavior of the vector form factor and the four-fermion cross section in a spontaneously broken SU(2) gauge…
The double logarithmic terms $\alpha_{s} \ln^{2}x $ are important to predict precisely the small $x$ behavior of the spin structure function $g_{1}$. We numerically analyze the evolution of the flavor non-singlet $g_{1}$ including the…
We evaluate the two-loop ${\cal O}(m_e^2/s)$ contribution to the wide-angle high-energy electron-positron scattering in the double-logarithmic approximation. The origin and the general structure of the power-suppressed double logarithmic…
We compute the two-loop corrections of O(alpha_s^2) to the Yukawa couplings in the framework of the Minimal Supersymmetric Standard Model (MSSM). The calculation is performed using the effective Lagrangian approach under the approximation…
The order $\alpha_s$ corrections to the Wilson coefficients of the dipole operators ($O_7,O_8$) at the matching scale $\mu =m_W$ are a crucial ingredient for a complete next- to-leading logarithmic calculation of the branching ratio for $b…
In this paper the complete two-loop corrections to the Higgs-boson decay, H -> gamma gamma, are presented. The evaluations of both QCD and electroweak corrections are based on a numerical approach. The results cover all kinematical regions,…
The momentum dependent two-loop contributions of the order $\mathcal{O}$($\alpha_s \alpha_t$) to the masses in the Higgs-boson sector of the MSSM are computed. Adopting the Feynman-diagrammatic approach and using a mixed…
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,…
We perform the calculation of all relativistic and quantum electrodynamic corrections of the order of $\alpha^6\,m$ to the ground electronic state of a hydrogen molecule and present improved results for the dissociation and the fundamental…
Contributions to HFS and to the Lamb shift intervals of order $\alpha^2(Z\alpha)^5$ induced by graphs with two radiative photons inserted in the electron line are considered. It is demonstrated that this last gauge invariant set of diagrams…
The QCD beta-function and the anomalous dimensions for the Coulomb potential and the static potential first differ at three loop order. We evaluate the three loop ultrasoft anomalous dimension for the Coulomb potential and give the complete…
We present in analytic form the three-loop O(\alpha_s^2) correction to the H -> gg partial width of the standard-model Higgs boson with intermediate mass M_H << 2 M_t. Its knowledge is required because the O(\alpha_s) correction is so…