Related papers: Matching at one loop for the four-quark operators …
In this work corrections to low energy punctual effective quark couplings up to the eighth order are calculated by considering vacuum polarization effects with the scalar quark-antiquark condensate. The departing point is a QCD-based NJL…
The non-perturbative renormalization of four-quark operators plays a significant role in lattice studies of flavor physics. For this purpose, we define regularization-independent symmetric momentum-subtraction (RI/SMOM) schemes for Delta…
I present an introduction to the NRQCD factorization method for calculating annihilation rates and inclusive production rates for heavy quarkonium. Using this method, annihilation decay rates and sufficiently inclusive cross sections are…
In this paper we discuss techniques, which lead to a significant improvement of the efficiency of the Monte Carlo integration, when one-loop QCD amplitudes are calculated numerically with the help of the subtraction method and contour…
The relation between the heavy-quark field in QCD and the corresponding field in HQET is derived up to three loops, and to all orders in the large-$\beta_0$ limit. The corresponding relation between the QED electron field and the…
Using staggered fermions, we calculate the perturbative corrections to the bilinear and four-fermion operators that are used in the numerical study of weak matrix elements for $\epsilon'/\epsilon$. We present results for one-loop matching…
We outline a strategy to efficiently include the electromagnetic interactions of the sea quarks in QCD+QED. When computing iso-spin breaking corrections to hadronic quantities at leading order in the electromagnetic coupling, the sea-quark…
We explore the effect of higher order operators in the non-relativistic formulation of QCD (NRQCD). We calculated masses in the b \bar b spectrum using quenched gauge configurations at beta = 6.0 and two different NRQCD actions which have…
We consider continuum-formulation QCD in four dimensions with twelve massless fundamental quark flavors. Splitting the SU(\(N\)) gauge field into background and fluctuation parts, we use well-developed techniques to calculate the one-loop…
We extend the recent one loop analysis of the ultraviolet completion of the $CP(N)$ nonlinear $\sigma$ model in six dimensions to two loop order in the MSbar scheme for an arbitrary covariant gauge. In particular we compute the anomalous…
The infrared exponentiation properties of dimensionally-regularized multi-loop scattering amplitudes are typically hidden at the level of the integrand, materializing only after integral evaluation. We address this long-standing problem by…
We provide results for the one-loop triple-collinear color/spin-space splitting operators for the five possible processes, $q \to qq'\bar{q}'$, $q \to qq\bar{q}$, $q \to qgg$, $g \to gq\bar{q}$ and $g \to ggg$. The expressions are exact in…
We consider Quantum Chromodynamics with external vector, axial-vector, scalar and pseudo-scalar currents and compute three-loop corrections to the corresponding vertex function taking into account massive quarks. We consider all non-singlet…
In this review, we present a new method for computing physical cross sections at NLO accuracy in QCD without using the standard Dimensional Regularisation. The algorithm is based on the Loop-Tree Duality theorem, which allow us to obtain…
I discuss the status of the computation of the two-loop QCD corrections to top-quark pair production associated with a jet at hadron colliders. This amplitude is a missing ingredient for next-to-next-to-leading order (NNLO) QCD predictions.…
A new method for computing hadronic effects on electroweak radiative corrections to low-energy weak interaction semileptonic processes is described. It employs high order perturbative QCD results originally derived for the Bjorken sum rule…
We study the electromagnetic on-shell form factor of quarks in massless perturbative QCD. We derive the complete pole part in dimensional regularization at three loops, and extend the resummation of the form factor to the…
We summarize recent results on the nonperturbative quark-gluon interaction in Landau gauge QCD. Our analytical analysis of the infrared behaviour of the quark-gluon vertex reveals infrared singularities, which lead to an infrared divergent…
In this talk, we review a QCD factorization based approach to extract parton distribution and correlation functions from lattice QCD calculation of single hadron matrix elements of quark-gluon operators. We argue that although the lattice…
We implement a cutoff-independent regularization of four-fermion interactions to calculate the color-superconducting gap parameter in quark matter. The traditional cutoff regularization has difficulties for chemical potentials \mu of the…