Related papers: O(\alpha_s^2) Corrections to Current Correlators
In this review some recent multi-loop results obtained in the framework of perturbative Quantum Chromodynamics (QCD) and Quantum Electrodynamics (QED) are discussed. After reviewing the most advanced techniques used for the computation of…
The $O(\alpha m_t^2/m_w^2)$ and $O(\alpha \alpha_s m_t^2/m_w^2)$ corrections to the partial decay width $\Gamma(Z \rightarrow b + \bar{b})$ are computed using the current algebra formulation of radiative corrections. This framework allows…
We describe several techniques for the calculation of multi-loop integrals and their application to heavy quark current correlators. As new results, we present the four-loop correction to the second and third physical moment in the…
We compute the next-to-leading order perturbative QCD corrections to the correlators of nucleon interpolating currents in relativistic nuclear matter. The main new result is the calculation of the O(alpha_s) perturbative corrections to the…
We have recently presented the complete O(alpha_s^2) corrections to the semileptonic decay width of the b quark at maximal recoil. Here we discuss various technical aspects of that calculation and further applications of similar methods. In…
We report about recent progress in computing four-loop massive correlators. The expansion of these correlators in the external momentum leads to vacuum integrals. The calculation of these vacuum integrals can be used to determine Taylor…
The analytization procedure which allows one to remove nonphysical singularities of the QCD running coupling constant $\bar\alpha_s(q^2)$ in the infrared region is applied to standard as well as to iterative solutions of the two-loop…
We compute next-to-leading order (NLO) perturbative QCD corrections to the correlators of interpolating pentaquark currents. We employ modular techniques in configuration space which saves us from the onus of having to do loop calculations.…
Using configuration space techniques, we calculate next-to-leading order (NLO) five-loop QCD corrections to the correlators of interpolating pentaquark currents in the limit of massless quarks. We obtain very large NLO corrections to the…
For high-pT forward processes at the Large Hadron Collider (LHC), QCD logarithmic corrections in the hard transverse momentum and in the large rapidity interval may both be quantitatively significant. The theoretical framework to resum…
Using the Schr\"odinger functional we have computed a variety of renormalized on-shell correlation functions to one-loop order of perturbation theory. By studying their approach to the continuum limit we have determined the O($a$)…
In this paper we consider the matching coefficients up to two loops between Quantum Chromodynamics (QCD) and Non-Relativistic QCD (NRQCD) for the vector, axial-vector, scalar and pseudo-scalar currents. The structure of the effective theory…
We review the current status of perturbative corrections in QCD at four loops for scattering processes with space- and time-like kinematics at colliders, with specific focus on deep-inelastic scattering and electron-positron annihilation.…
The calculation of massive three-loop QCD form factors using in particular the large moments method has been successfully applied to quarkonic contributions in [1]. We give a brief review of the different steps of the calculation and report…
The algorithm is described that enables one to perform an explicit summation of all the (\pi^2/ ln(Q^2/Lambda^2))^N corrections to \alpha_s (Q^2) that appear owing to the analytic continuation from spacelike to timelike region of momentum…
We present a semi-numerical method to compute one-loop corrections to processes involving many particles. We treat in detail cases with up to five external legs and massless internal propagators, although the method is more general.
We calculate the two-loop QCD correction to the scalar quark contributions to the electroweak gauge-boson self-energies at zero momentum-transfer in the supersymmetric extension of the Standard Model. We then derive the $O(\alpha_s)$…
We evaluate the corrections to the matching coefficient of the vector current between Quantum Chromodynamics (QCD) and Non-Relativistic QCD (NRQCD) to three-loop order containing a closed heavy-fermion loop. The result constitutes a…
2-point correlators of vector and axial currents, obtained from tau-decay data, are studied within the framework of perturbative QCD and Operator Product Expansion. Various sum rules, obtained from Borel transformation of the correlators in…
An overview is presented on the current status of main mathematical computation methods for the multi-loop corrections to single scale observables in quantum field theory and the associated mathematical number and function spaces and…