Related papers: Two-loop QCD corrections of the massive fermion pr…
The renormalised quark Dyson-Schwinger equation is studied in the limit of the renormalised current heavy quark mass m_R --> infinity. We are particularly interested in the analytic pole structure of the heavy quark propagator in the…
We calculate next-to-leading QCD corrections to the decay $H^+ \to u\bar d$ for generic up and down quarks in the final state. A recently developed algorithm for evaluation of massive two-loop Feynman diagrams is employed to calculate…
The running of renormalized quark masses is computed in lattice QCD with two flavors of massless O(a) improved Wilson quarks. The regularization and flavor independent factor that relates running quark masses to the renormalization group…
We present the leading colour and light fermionic planar two-loop corrections for the production of two photons and a jet in the quark-antiquark and quark-gluon channels. In particular, we compute the interference of the two-loop amplitudes…
We perform the non-perturbative (quenched) renormalization of the chromo-magnetic operator in Heavy Quark Effective Theory and its three-loop matching to QCD. At order 1/m of the expansion, the operator is responsible for the mass splitting…
The leading heavy-top two-loop corrections to the \Zbb~vertex are determined from a direct evaluation of the corresponding Feynman diagrams in the large \Mt~limit. %The calculation is done in the naive %dimensional regularization scheme…
We calculate and discuss the one-loop corrections to the photon sector of QED interacting to a background gravitational field. At high energies the fermion field can be taken as massless and the quantum terms can be obtained by integrating…
In the Minimal Supersymmetric Standard Model (MSSM) we incorporate the Higgs-boson propagator corrections, evaluated up to two-loop order, into the prediction of $\Gamma$(h -> ff) and BR(h -> ff) for f = b, c, $\tau$. The propagator…
Light quark masses can be determined through lattice simulations in regularization invariant momentum-subtraction(RI/MOM) schemes. Subsequently, matching factors, computed in continuum perturbation theory, are used in order to convert these…
We study two-loop anomalous dimension matrices in QCD and related gauge theories for products of Wilson lines coupled at a point. We verify by an analysis in Euclidean space that the contributions to these matrices from diagrams that link…
We consider a mixed system of unstable Majorana fermions in a general parity-nonconserving theory and renormalize its propagator matrix to all orders in the pole scheme, in which the squares of the renormalized masses are identified with…
We perform an analytic calculation of the one-loop amplitude for the W-boson mediated process 0 \to d u-bar Q Q-bar l-bar l, retaining the mass for the quark Q. The momentum of each of the massive quarks is expressed as the sum of two…
We present the light-quark mass dependence of the $\Lambda(1405)$ resonance at leading order in a renormalizable framework of covariant chiral effective field theory. The meson-baryon scattering amplitudes, which are obtained by solving the…
We review a new technique for the calculation of two-loop amplitudes and discuss as an example the fermionic contributions to e+ e- --> q qbar g.
A summary of recent results obtained for higher-order corrections to precision observables in the Standard Model and the Minimal Supersymmetric Standard Model is given. In the Standard Model electroweak two-loop results valid for arbitrary…
Using automated perturbation theory techniques, we have computed the one-loop mass of Fermilab fermions, with an improved gluon action. We will present the results of these calculations, and the resulting predictions for the charm and…
We report our recent numerical studies on two-color QCD with Wilson fermions. First the phase structure of the system in (kappa,mu)-plane is analyzed by measuring Polyakov line, baryon number density, gluon energy density and Polyakov line…
We compute the two-loop QCD corrections to amplitudes for processes $g g \to H g, q g \to H q$ and $q \bar{q} \to H g$ in the limit when the Higgs transverse momentum is larger than the top quark mass, $p_\perp \gg m_t$. These amplitudes…
The inclusive radiative decay of the B meson is known to provide strong constraints on many popular extensions of the Standard Model. Such constraints crucially depend on precision of the Standard Model predictions. One of the main…
We calculate all those QCD $N$-point functions which are relevant for a three-loop QCD thermodynamics calculation with finite quark masses within the hard the thermal loop approximation. Using the effective quark propagator, we also…