Related papers: Higher-twist contributions in exclusive processes
We consider the Generalized Parton Distributions for spin-1 nuclei in general and on the deuteron in particular. We use the impulse approximation to obtain a convolution model for them. Sum rules are used to check the validity of the…
We have made the first measurements of the virtual Compton scattering (VCS) process via the H$(e,e'p)\gamma$ exclusive reaction in the nucleon resonance region, at backward angles. Results are presented for the $W$-dependence at fixed…
We show that lepton-pair production in Virtual Compton Scattering offers, through interference with the well-known Bethe-Heitler process, a sensitive probe to learn the longitudinal response of resonances and the electromagnetic nucleon…
We explore the deeply virtual Compton scattering process at NLO with the emphasis on the measurement of the tensor gluon skewed distributions. We recalculate the one-loop coefficient function and give two-loop results for anomalous…
Hard exclusive leptoproduction of real photons from an unpolarized proton target is studied in an effort to elucidate generalized parton distributions. The data accumulated during the years 1996--2005 with the HERMES spectrometer are…
Hard exclusive leptoproductions of real photons, lepton pairs and mesons are the most promising tools to unravel the three-dimensional picture of the nucleon, which cannot be deduced from conventional inclusive processes like deeply…
The higher twist corrections $h^N(x)/Q^2$ to the spin dependent proton and neutron structure functions $g_1^N(x, Q^2)$ are extracted in a model independent way from experimental data on $g_1^N$ and found to be non-negligible. It is shown…
Infrared renormalons and $1/Q^2$ power corrections in deep-inelastic sum rules are studied. The renormalization of operators with power divergence are discussed. The higher-twist terms in the operator product expansion are shown to account…
We discuss interplay between the high-twist (HT) terms in the operator-product expansion and the next-to-next-to-leading-order (NNLO) QCD corrections to the deep-inelastic-scattering structure functions in analysis of the high-precision…
Using the similarity between twist 3 contributions to transverse spin for usual parton distributions and transverse momentum for non-diagonal parton distributions, we determine for the simple case of a scalar (pion, $He^4$) target the…
The overlap representation of skewed parton distributions is discussed and applications to wide-angle Compton scattering and electroproduction of mesons are presented. The amplitudes for these processes factorise into parton-level…
We investigate the 1/Q^2 power-suppressed corrections to structure functions in the flavour-singlet channel of deep inelastic lepton scattering arising from renormalon insertions into an initial-state gluon, as obtained using the dispersive…
We calculate polarization phenomena for virtual Compton scattering on protons, at relatively large momentum transfer 1 GeV$^2$ $\le -q^2\le$ 5 GeV$^2$ on the basis of a model for $\gamma^*+ p\to \gamma+p$ with two main contributions:…
In material testing applications, Computed Tomography is a well established imaging technique that allows the recovery of the attenuation map of an object. Conventional modalities exploit only primary radiation and although in the energy…
Off-diagonal parton distributions occur in several hard exclusive reactions. They extend the study of hadron structure beyond what can be learned from ordinary distributions and have a particularly rich spin structure. The hard scattering…
Using dispersion relations, we derive the complete virtual QED contributions to Bhabha scattering due to vacuum polarization effects in photon propagation. We apply our result to hadronic corrections and to heavy lepton and top quark loop…
We perform an exploratory study of higher twist contributions to deep inelastic scattering. We estimate the size of two major sources of higher twist, namely absorptive corrections and the vector meson dominance (VMD) contribution. We find…
Recently dispersion relations have been applied to hard exclusive processes such as deeply virtual Compton scattering, and a holographic principle was proposed that maps out the generalized parton distributions entering the soft matrix…
We study the electromagnetic Bethe-Heitler type contribution to neutrino-induced deeply virtual meson production (\nuDVMP). Such O(\alpha_{em})-corrections decrease with Q^{2} in the Bjorken regime less steeply than the standard \nuDVMP…
The twist-2 contributions to the polarized structure functions in deep inelastic lepton--hadron scattering are calculated including the exchange of weak bosons and using both the operator product expansion and the covariant parton model. A…