Related papers: Two-loop corrections to QCD $\theta$ angle from ev…
We compute the two-loop BSM contributions to the $h\longrightarrow \gamma\gamma$ decay width in the SM extended with a real triplet of $SU(2)$. We consider scenarios in which the neutral components of doublet and triplet do not mix, so that…
The resummed expression for the quark form factor illustrates the fact that dimensional continuation provides a regularization not only for ultraviolet and infrared singularities of fixed order QCD amplitudes, but also for the Landau pole…
The renormalization group evolution of $\Delta B=2$ transition operators is studied at leading order in heavy quark effective theory and at next-to-leading order in QCD. We calculate new contributions that were not taken into account in…
We calculate the four-top quark operator contributions to the two-loop renormalization constants of the fermion and gluon fields, necessary to obtain the renormalization group equations for the fermion masses and the strong coupling…
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…
We present a proof of the factorization of renormalization scheme in one-loop-corrected Fierz identities. This scheme factorization facilitates the simultaneous transformation of operator basis and renormalization scheme using only…
Three-loop $\beta$-functions of the Minimal Supersymmetric Standard Model regularized by higher covariant derivatives are obtained for an arbitrary supersymmetric subtraction scheme. For this purpose we first calculate two-loop anomalous…
We present the renormalization constant of the pseudoscalar operator defined with a non-anticommuting $\gamma_5$ in dimensional regularization up to four-loop order in perturbative Quantum Chromodynamics (QCD). Furthermore, by virtue of…
The overview is given of the results obtained recently in the course of renormalization-group (RG) study of two-dimensional (2D) models. RG functions of the two-dimensional n-vector \lambda \phi^4 Euclidean field theory are written down up…
A comprehensive study is performed of two-loop Feynman diagrams with three external legs which, due to the exchange of massless gauge-bosons, give raise to infrared and collinear divergencies. Their relevance in assembling realistic…
We present the two-loop virtual QCD corrections to the scattering of massless identical quarks, q qbar to q qbar, in conventional dimensional regularisation and using the MSbar scheme. The structure of the infrared divergences agrees with…
We compute the renormalization functions on the lattice, in the RI' scheme, of local bilinear quark operators $\bar{\psi}\Gamma\psi$, where $\Gamma= 1, \gamma_5, \gamma_\mu, \gamma_5\gamma_\mu, \gamma_5\sigma_{\mu\nu}$. This calculation is…
We calculate quantum corrections to the symmetry generators for the transversity operators in quantum chromodynamics (QCD) in the two-loop approximation. Using this result, we obtain the evolution kernel for the corresponding operators at…
It is becoming more important to subtract renormalons efficiently from perturbative calculations, in order to achieve high precision QCD calculations. We propose a new framework ``Dual Space Approach" for renormalon separation, which…
We present closed analytic expressions of the electromagnetic vertex form factors for heavy quarks at the two-loop level in QCD for arbitrary momentum transfer. The calculation is carried out in dimensional regularization. The electric and…
Within the framework of $B$-meson light-cone sum rules, we compute the one-loop level QCD corrections to $B\to \pi$ transition form factors at small $ q^{2}$ region, in implement of a complete renormalization group equation evolution. To…
We present the analytic evaluation of the second-order corrections to the massive form factors, due to two-loop vertex diagrams with a vacuum polarization insertion, with exact dependence on the external and internal fermion masses, and on…
We consider the two-fold expansion in powers of the conformal anomaly and of the strong coupling $\alpha_s$ for the non-singlet contributions to Adler $D$-function and Bjorken polarized sum rule calculated previously in the $\MSbar$-scheme…
A novel method to treat effects from evanescent operators in next-to-leading order (NLO) computations is introduced. The approach allows, besides further simplifications, to discard evanescent-to-physical mixing contributions in NLO…
The anomalous dimension of spin-1/2 baryon operators in QCD is derived at leading 1/Nf order using the minimal subtraction scheme. A residual ambiguity, originating from the presence of evanescent operators in dimensional regularization, is…