Related papers: Operator product expansion in static-quark effecti…
We calculate the next-to-leading order QCD corrections to the perturbative term in the operator product expansion of the spectral functions of light tetraquark currents. By using also configuration space methods we keep the momentum space…
We give a recurrence relation for two-loop integrals encountered in the effective field theory of an infinitely heavy quark, Q, interacting with gluons and Nl massless quarks, q, from which we obtain exact two-loop results, in any dimension…
We develop a general approach to the calculation of target mass and finite t=(p'-p)^2 corrections in hard processes which can be studied in the framework of the operator product expansion and involve momentum transfer from the initial to…
The present calculations in perturbative QCD reach the order $\alpha_s^4$ for several correlators calculated to five loops, and the huge computational difficulties make unlikely the full six-loop calculation in the near future. This…
The short-distance expansion of the heavy-light currents $\bar q\,\gamma^\mu Q$ and $\bar q\,\gamma^\mu\gamma_5\,Q$ is constructed to order $1/m_Q$, and to next-to-leading order in renormalization-group improved perturbation theory. It is…
We introduce and study the properties of the "color-straight" four-quark operators containing heavy and light quark fields. They are of the form (\bar b\Gamma_b b)(\bar q\Gamma_q q) where both brackets are color singlets. Their expectation…
We present exact results, at next-to-leading order in renormalization-group improved perturbation theory, for the Wilson coefficients appearing at order 1/m_Q in the heavy-quark expansion of heavy-light current operators. To this end, we…
We provide a brief introduction to the high density effective theory of QCD. As an application, we consider the instanton correction to the perturbatively generated gap in the color superconducting phase. We show that the instanton…
We study how to compute the operator product expansion coefficients in the exact renormalization group formalism. After discussing possible strategies, we consider some examples explicitly, within the $\epsilon$-expansions, for the…
We give a formula for the derivatives of a correlation function of composite operators with respect to the parameters (i.e., the strong fine structure constant and the quark mass) of QCD in four-dimensional euclidean space. The formula is…
Perturbation expansions appear to be divergent series in many physically interesting situations, including in quantum field theories like quantum electrodynamics (QED) and quantum chromodynamics (QCD), where the perturbative coefficients…
A technique of large-charge expansion provides a novel opportunity for calculation of critical dimensions of operators $\phi^Q$ with fixed charge $Q$. In the small-coupling regime the polynomial structure of the anomalous dimensions can be…
Nucleon structure functions can be observed in Deep Inelastic Scattering experiments, but it is an outstanding challenge to confront them with fully non-perturbative QCD results. For this purpose we investigate the product of…
We calculate perturbative renormalization constants for the \Delta B=2 four-quark operators in lattice NRQCD. Continuum operators \bar{b}\gamma_{\mu}(1-\gamma_5)q~ \bar{b}\gamma_{\mu}(1-\gamma_5)q and…
We find the leading electroweak corrections to the Lagrangians of heavy-quark effective theory and nonrelativistic QCD. These corrections appear in the Wilson coefficients of the two- and four-quark operators and are considered here at…
The perturbation series for the renormalization group functions of the $O(N)-$symmetric $\phi^4$ field theory are divergent but asymptotic. They are usually followed by Resummation calculations to extract reliable results. Although the same…
In this work, we compute the anomalous dimensions of the $\phi^Q$ operator in six-dimensional cubic scalar theory. The renormalization analysis is carried out within the framework of the Operator Product Expansion method, while the…
We evaluate the electromagnetic spectral function in QCD plasma in a nonperturbative background of in-medium quark and gluon condensates by incorporating the leading order power corrections in a systematic framework within the ambit of the…
The two-loop massive operator matrix elements for the fermionic local twist--2 operators with external massive fermion lines in Quantum Electrodynamics (QED) are calculated up to the constant terms in the dimensional parameter $\epsilon = D…
In Refs. [1,2] we determined the infinite volume coefficients of the perturbative expansions of the self-energies of static sources in the fundamental and adjoint representations in SU(3) gluodynamics to order $\alpha^{20}$. We used…