Related papers: Higher-twist contributions in exclusive processes
The soft physics approach to Compton scattering at moderately large momentum transfer is reviewed. It will be argued that in that approach the Compton cross section as well as other exclusive observables exhibit approximate scaling in a…
We present a Machine Learning based approach to the cross section and asymmetries for deeply virtual Compton scattering from an unpolarized proton target using both an unpolarized and polarized electron beam. Machine learning methods are…
Single pseudoscalar and vector mesons hard semi-inclusive photoproduction $\gamma h \to MX" via higher twist (HT) mechanism is calculated using the QCD running coupling constant method. The structure of infrared renormalon singularities of…
We consider exclusive $pp \to pp \pi^{+} \pi^{-}$ and $pp \to pp \pi^{+} \pi^{-}\pi^{+} \pi^{-}$ reactions at high energies. The calculation is based on a tensor pomeron model and the amplitudes for the processes are formulated in an…
We report on a recent extraction of the higher twist contributions to the deep inelastic structure functions $F_2^{ep,ed}(x,Q^2)$ in the large $x$ region. It is shown that the size of the extracted higher twist contributions is strongly…
We describe the hard leptoproduction of transversally polarized rho-meson, up to twist 3 accuracy, including 2- and 3- particles Fock-states, in the HERA kinematics of high center-of-mass energy. We first build a model based on a simple…
The twist-3 contribution, consisting of twist-2 transversity generalized parton distributions (GPDs) and a twist-3 meson wave function, to deeply virtual pion electroproduction is discussed. The twist-3 meson wave function includes both the…
We investigate the Q^2 evolution of parton distributions at small x values, obtained in the case of flat initial conditions. The contributions of twist-two and (renormalon-type) higher-twist operators of the Wilson operator product…
We calculate the kinematic twist-3 and 4 corrections to the leading order amplitude of timelike Compton scattering (TCS) on a (pseudo-)scalar target, in the recently developed framework based on the conformal operator-product expansion.…
The contribution of the higher-twist mechanism to the large-$p_T$ inclusive gluon production cross section in $\pi p$ collisions is calculated in case of the principle of maximum conformality and Brodsky-Lepage-Mackenzie approaches in the…
We discuss possibilities of measurement of deeply virtual Compton scattering amplitudes via different asymmetries in order to access the underlying skewed parton distributions. Perturbative one-loop coefficient functions and two-loop…
We study the kaon leptoproduction on the basis of the handbag approach. We consider the leading-twist contribution together with the transversity twist-3 effects which were found to be important in the description of pseudo-scalar meson…
We review the possibility to use the renormalons emerging in the perturbation series of the twist-2 part of the nonsinglet structure functions FL, F2, F3, and g1 to make approximate predictions for the magnitude of the appertaining twist-4…
Coherent hard exclusive reactions on light nuclei provide access to their quark and gluon structure and enable three-dimensional tomography of these complex systems. We study deeply virtual Compton scattering on a helium-4 target, including…
In this paper we analyze deep inelastic one-particle inclusive processes for the case of spin-one targets or for the case of spin-one produced hadrons, such as rho mesons. This allows the measurement of new distribution and fragmentation…
We calculate the contribution of the higher twist Feynman diagrams to the large-$p_T$ inclusive pion production cross section in proton-proton collisions in the case of the running and frozen coupling approaches within holographic QCD. The…
We investigate exclusive electroproduction of vector and pseudoscalar mesons at large photon virtuality $Q^2$. These reactions were analyzed within the handbag approach where amplitudes factorize into hard subprocesses and generalized…
We discuss the handbag approximation to exclusive deep virtual Compton scattering. After defining the kinematical region where this approximation can be valid, we propose tests for its relevance in planned electroproduction experiments, e +…
The scaling behavior of large-pT hadron production in hadronic collisions is investigated. A significant deviation from the NLO QCD predictions is reported, especially at high values of xT=2pT/sqrt(s). In contrast, the prompt photon and jet…
We discuss the evaluation of power corrections to hard scattering and decay processes for which an operator product expansion is applicable. The Wilson coefficient of the leading-twist operator is the difference of two perturbative series,…