Related papers: Two-Loop Calculations with Vertex Corrections in t…
We compute the dominant logarithmically enhanced two-loop electroweak corrections to the electron-positron scattering differential cross section in the high energy limit for large scattering angles. Depending on the scattering angle and…
We consider two-loop leading and next-to-leading logarithmic virtual corrections to arbitrary processes with external massless fermions in the electroweak Standard Model at energies well above the electroweak scale. Using the…
During the last year, analytic expressions for the two-loop QCD corrections to the form factors for the vector, axial-vector, scalar and pseudo-scalar vertices involving a pair of heavy quarks, $Q \bar{Q}$, were calculated. The results are…
The present paper pertains to corrections which are due to the presence of beam-limiting and beam-shaping devices in proton planning. Two types of corrections are considered: those which are due to the nonzero thickness of such devices…
We systematically analyze the $d=5$ Weinberg operator at 2-loop order. Using a diagrammatic approach, we identify two different interesting categories of neutrino mass models: (i) Genuine 2-loop models for which both, tree-level and 1-loop…
Recent results for higher-order corrections to the relation between the vector-boson masses in the Standard Model and Supersymmetry are summarized. In the Standard Model, the Higgs-mass dependence of the two-loop contributions to Delta r is…
We construct a specific formalism for calculating the one-loop virtual corrections for standard model processes with an arbitrary number of external legs. The procedure explicitly separates the infrared and ultraviolet divergences…
We compute the massive gauge and scalar corrections to form factors in both the Sudakov and threshold regimes up to and including two-loop orders. The corrections are calculated for processes involving two external fermions and scalars in…
Recently it was discovered that the Standard Model vacuum may suffer an essential metastability near the Planck scale. In this regard it makes sense to study in more detail the decay processes of the metastable vacuum and to develop methods…
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…
We investigate a specific set of two-loop self-energy corrections involving squared decay rates and point out that their interpretation is highly problematic. The corrections cannot be interpreted as radiative energy shifts in the usual…
The inclusion of the unstable features of a spin-1 particle, without breaking the electromagnetic gauge invariance, can be properly accomplished by including higher order contributions as done in the so-called fermion loop scheme (for the W…
We overview the general status of higher order corrections to Bhabha scattering and review recent progress in the determination of the two-loop virtual corrections. Quite recently, they were derived from combining a massless calculation and…
Recent results on the entirely analytic calculation of second order corrections to massive quark pair production vertices induced by light quark flavours are reviewed. Based on the method presented in this talk the second order effects of…
Details of the two-loop analysis of long-distance QED radiative corrections to neutron beta decay are presented. Explicit expressions are given for hard, jet, and soft functions appearing in the factorization formula that describes the…
We estimate the two-photon exchange corrections to both proton and neutron electromagnetic physical observables in a relativistic light cone quark model. At a fixed momentum transfer the corrections are found to be small in magnitudes, but…
A variational study of two-nucleon systems with lattice quantum chromodynamics is performed using a wide range of interpolating operators: dibaryon operators built from products of momentum-projected nucleons, hexaquark operators built from…
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…
We analyse the size of quantum corrections in the Zee model using effective field theory techniques. We derive the relevant 1-loop matching conditions and use them together with the existing renormalisation group equations in the two Higgs…
One-loop corrections at the two-nucleon level to Pion Double Charge exchange (DCX) scattering off a nuclear target at threshold, are calculated within the framework of Heavy Baryon Chiral Perturbation Theory (HBChPT). An estimate for the…