相关论文: The QCD beta-function at O(1/N_f)

We review the computation of the anomalous dimensions of the twist-2 unpolarized operators in the large N_f expansion. Results are discussed for the predominantly gluonic singlet operator and the O(1/N_f) part of the 3-loop splitting…

QED based on $\theta$-unexpanded noncomutative space-time in contrast with the noncommutative QED based on $\theta$-expanded U(1) gauge theory via the Seiberg-Witten map, is one-loop renormalizable. Meanwhile it suffers from asymptotic…

Deep inelastic scattering data on F2 structure function from various fixed-target experiments were analyzed in the non-singlet approximation with a next-to-next-to-leading-order accuracy. The study of high statistics deep inelastic…

We investigate the reliability of the large $N_f$ expansion of four-dimensional gauge-fermion quantum field theories, focusing on the structure and scheme dependence of the beta function. While the existence of a nontrivial UV fixed point…

We apply the Schrodinger functional method to the Abelian gauge theory in three dimensions with Nf=2 four-component fermions. We find that the calculated beta function does not cross zero in the range of coupling we study. This implies that…

An exact formula is derived for the infrared singularities of dimensionally regularized scattering amplitudes in massless QCD with an arbitrary number of legs, valid at any number of loops. It is based on the conjecture that the…

We study extremal correlation functions of chiral primary operators in the large-N SU(N) ${\cal N} = 2$ superconformal QCD theory and present new results based on supersymmetric localization. We discuss extensively the basis-independent…

We revisit the question of whether or not one can perform reliable semiclassical QCD computations at zero temperature. We study correlation functions with no perturbative contributions, and organize the problem by means of the operator…

For the case of $n$-jet production at next-to-next-to-leading order in the QCD coupling, in the infrared divergent corners of phase space where particles are collinear or soft, one must evaluate $(n+1)$-parton final-state one-loop…

We compute the four loop term of the mass anomalous dimension in the two dimensional Gross-Neveu model in the MSbar scheme. The absence of multiplicative renormalizability which results when using dimensional regularization means that the…

The next-to-next-to-leading order (NNLO) non-singlet QCD analysis of the experimental data of the CCFR collaboration for the $xF_3$ and $F_2$ structure functions of the deep-inelastic scattering of neutrinos and antineutrinos on the nucleon…

The new theoretical input to the analysis of the experimental data of the CCFR collaboration for $F_3$ structure function of $\nu N$ deep inelastic scattering is considered. This input comes from the next-to-next-to-leading order…

We discuss Pad\'e-improvement of known four-loop order results based upon an asymptotic three-parameter error formula for Pad\'e-approximants. We derive an explicit formula estimating the next-order coefficient $R_4$ from the previous…

We present results for the O(alpha_s) virtual corrections to q g -> W b bbar q' obtained with a new automatized approach to the evaluation of one-loop amplitudes in terms of Feynman diagrams. Together with the O(alpha_s) corrections to q q'…

We present analytical results at four-loop level for the $\beta$-function of the coupling of a generic gauge group and any number of different quark representations. From this we can directly derive the gluino contribution to the strong…

We evaluate the complete four-loop anomalous dimension matrix that is necessary for determining the effective flavour-changing neutral current couplings qbar-q'-gamma and qbar-q'-g at the next-to-next-to-leading order in QCD. The resulting…

This PhD thesis is a first step towards the control of the quantum corrections in the Resonance Chiral Theory, the suggested framework to handle QCD in the resonance region. After a theoretical introduction, Chapter 3 is devoted to…

The decay rate of neutrinoless double beta ($0\nu\beta\beta$) decay contains terms from heavy particle exchange, which lead to dimension-9 (d=9) six fermion operators at low energies. Limits on the coefficients of these operators have been…

We report a calculation of approximate next-to-next-to-leading-order (N$^2$LO) and next-to-N$^2$LO (N$^3$LO) QCD corrections to associated $tW$ production at the LHC, which constitute the dominant contributions to full perturbative…

The noncommutative dipole QED is studied in detail for the matter fields in the adjoint representation. The axial anomaly of this theory is calculated in two and four dimensions using various regularization methods. The Ward-Takahashi…