Related papers: Two Loop QCD Vertices and Three Loop MOM $\beta$ f…
We compute the complete one-loop corrections to the simplest class of QCD gluon amplitudes, those with two color-adjacent opposite-helicity external particles. We present results for an arbitrary number of external legs. The computation…
We calculate the four-loop massless QCD corrections with two closed quark lines to quark and gluon form factors. The results for the gluon form factor and the singlet part of the quark form factor are given for the first time. From our…
We compute the planar three-loop Quantum Chromodynamics (QCD) corrections to the helicity amplitudes involving a vector boson $V=Z,W^\pm,\gamma^*$, two quarks and a gluon. These amplitudes are relevant to vector-boson-plus-jet production at…
An overview of Chiral Perturbation Theory calculations in the mesonic sector at the two Loop level is given. Discussed in some detail are the partially quenched case relevant for lattice QCD, the general fitting procedures and $\pi\pi$,$\pi…
We present the calculation of the mixed two-loop QCD/electroweak corrections to hadronic W boson decays within the Standard Model. The optical theorem is applied to the W boson two-point function. The multi-scale integrals are computed with…
This brief note is devoted to a study of genuine non-perturbative corrections to the Landau gauge ghost-gluon vertex in terms of the non-vanishing dimension-two gluon condensate. We pay special attention to the kinematical limit which the…
Quantum electrodynamics (QED) fixed in the 't~Hooft-Veltman gauge is renormalized to three loops in the MSbar scheme. The beta-functions and anomalous dimensions are computed as functions of the usual QED coupling and the additional…
We describe the calculation of the three-loop QCD corrections to quark and gluon form factors. The relevant three-loop Feynman diagrams are evaluated and the resulting three-loop Feynman integrals are reduced to a small set of known master…
Dimensional Reduction is applied to \qcd{} in order to compute various renormalization constants in the \drbar{} scheme at higher orders in perturbation theory. In particular, the $\beta$ function and the anomalous dimension of the quark…
We use on-shell recursion relations to determine the one-loop QCD scattering amplitudes with a massless external quark pair and an arbitrary number (n-2) of positive-helicity gluons. These amplitudes are the last of the unknown infrared-…
Baryons of lower spin in partially quenched large-$N_c$ QCD are studied with particular emphasis to interpolation between standard unquenched and fully quenched limits. In large $N_c$ limit of partially quenched QCD, we calculate $\Delta…
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…
The computation of one-loop corrections to Reggeon-Particle-Particle effective vertices with two scales of virtuality is considered in the framework of gauge-invariant effective field theory for Multi-Regge processes in QCD. Rapidity…
We compute three-loop QCD corrections to the scattering amplitude of a Higgs boson and three partons interfered with its tree level counterpart. Specifically, we derive our results in the generalized leading color limit. Our results are…
This paper is a first report on the determination of $\Lambda_{\msbar}$ from lattice simulations with 2+1+1 twisted-mass dynamical flavours {\it via} the computation of the ghost-gluon coupling renormalized in the MOM Taylor scheme. We show…
We present the first results from a study of the quark--gluon vertex function in the Landau gauge. The results are obtained for quenched QCD with an O(a)-improved Wilson fermion action, at beta=6.0. We discuss plans for further study,…
We investigate the occurrence of power terms $(Lambda^2/p^2$ in the running QCD coupling by analysing non-perturbative measurements of $\alpha_s(p)$ at quite low momenta obtained from the lattice three-gluon vertex. Our study provides some…
The resummation of soft gluon exchange for QCD hard scattering requires a matrix of anomalous dimensions, which has been computed through two loops. The two-loop matrix is proportional to the one-loop matrix. Recently there have been…
Chirally enhanced supersymmetric QCD corrections to FCNC processes are investigated in the framework of the MSSM with generic sources of flavor violation. These corrections arise from flavor-changing self-energy diagrams and can be absorbed…
We present examples of on-shell recurrence relations for determining rational functions appearing in one-loop QCD amplitudes. In particular, we give relations for one-loop QCD amplitudes with all legs of positive helicity, or with one leg…