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We present an overview of fractional analytic QCD beyond leading order, following the results recently obtained in Ref. [1]. We demonstrate four different representations, the details of their derivation, and show the applicability of…
We study the heavy-quark contribution to the proton structure functions F_2^i(x,Q^2) and F_L^i(x,Q^2), with i=c,b, for small values of Bjorken's x variable at next-to-lading order and provide compact formulas for their ratios…
We compute for the first time the next-to-leading-order QCD corrections to the $\bar B_{(s)} \to D_{(s)}^{(\ast)}$ form factors at large hadronic recoil. Both the charm-quark-mass and the strange-quark-mass dependent pieces can generate the…
We investigate the influence of higher twist corrections to deep inelastic structure functions in the low-$Q^2$ and small-$x$ HERA region. We review the general features of the lowest-order QCD diagrams which contribute to twist-4 at…
We report on a recently completed, first calculation of the full next-to-leading order QCD corrections for heavy flavor contributions to the inclusive structure function $g_1$ in longitudinally polarized deep-inelastic scattering. All…
We summarize our recent results on small x resummation in full QCD with n_f quark flavours and discuss their phenomenological impact in the extraction of parton distributions from present day structure function data and their extrapolation…
We discuss the order alpha_s^2 corrections to the longitudinal spin structure function g_1(x,Q^2,m^2) which are due to heavy flavour contributions. Here Q denotes the virtuality of the photon and m stands for the heavy flavour mass. Since…
We discuss the QCD effects of the higher-twist operators in the nucleon spin-dependent structure functions measured by the polarized deep inelastic leptoproduction. We particularly study the renormalization of the twist-3 and twist-4…
The recent conundrum with the proton charge radius inspires reconsideration of the corrections that enter into determinations of the proton size. We study the two-photon proton-structure corrections, with special consideration of the…
We show that the ratio of different structure functions have a maximum which depends on $x_B$ and $A$. We argue that these maxima are proportional to the saturation scale. The analysis of leading and higher twist contributions for different…
We show how perturbation theory may be reorganized to give splitting functions which include order by order convergent sums of all leading logarithms of $x$. This gives a leading twist evolution equation for parton distributions which sums…
I consider variations in the definitions, at next-to-leading order (NLO) and at next-to-next-to leading order (NNLO), of a General-Mass Variable Flavour Number Scheme (GM-VFNS) for heavy flavour structure functions. I also define a new…
Quark-hadron duality is studied in a systematic way for polarized and unpolarized structure functions, by taking into account all the available data in the resonance region. In both cases, a precise perturbative QCD based analysis of the…
A phenomenological parameterization of the proton polarized structure function has been developed for x > 0.02 using deep inelastic data up to ~ 50 (GeV/c)**2 as well as available experimental results on both photo- and electro-production…
We study power corrections in the Drell-Yan (DY) process using state-of-the-art predictions for both neutral and charged current production. For both types of DY processes, we account for power corrections arising from bottom and charm…
Double parton distributions can be computed from the perturbative splitting of one parton into two if the distance between the two observed partons is small. We develop schemes to take into account quark mass effects in this computation,…
We consider top quark production and decay in the narrow width approximation and study if the polarisation effects, that manifest themselves in correlations of angular distributions of particles from top quark decays and final state jets in…
A method for calculating the pion structure function directly in terms of light-cone wave functions is suggested. Taking twist-2 and twist-4 pion light-cone wave functions into account, it is shown that the QCD sum rule prediction is in…
We present a first QCD analysis of next-to-next-leading-order (NNLO) contributions of the spin-dependent parton distribution functions (PPDFs) in the nucleon and their uncertainties using the Jacobi polynomial approach. Having the NNLO…
To have an analytic understanding of the higher-twist structure functions, we calculate twist four longitudinal structure function for a positronium-like bound state in weak coupling light-front QED. We find that in the weakly coupled…